Everolimus is a potent inducer of erythroid differentiation and gamma-globin gene expression in human erythroid cells

Pharmacogenomics of Drugs Used in β-Thalassemia and Sickle-Cell Disease: From Basic Research to Clinical Applications

In this short review we have presented and discussed studies on pharmacogenomics (also termed pharmacogenetics) of the drugs employed in the treatment of β-thalassemia or Sickle-cell disease (SCD). This field of investigation is relevant, since it is expected to help clinicians select the appropriate drug and the correct dosage for each patient. We first discussed the search for DNA polymorphisms associated with a high expression of γ-globin genes and identified this using GWAS studies and CRISPR-based gene editing approaches. We then presented validated DNA polymorphisms associated with a high HbF production (including, but not limited to the HBG2 XmnI polymorphism and those related to the BCL11A, MYB, KLF-1, and LYAR genes). The expression of microRNAs involved in the regulation of γ-globin genes was also presented in the context of pharmacomiRNomics. Then, the pharmacogenomics of validated fetal hemoglobin inducers (hydroxyurea, butyrate and butyrate analogues, thalidomide, and sirolimus), of iron chelators, and of analgesics in the pain management of SCD patients were considered. Finally, we discuss current clinical trials, as well as international research networks focusing on clinical issues related to pharmacogenomics in hematological diseases.

Ginsenoside Rg1 promotes fetal hemoglobin production in vitro: A potential therapeutic avenue for β-thalassemia

β-thalassemia, a globally prevalent genetic disorder, urgently requires innovative treatment options. Fetal hemoglobin (HbF) induction stands as a key therapeutic approach. This investigation focused on Ginsenoside Rg1 from the Panax genus for HbF induction. Employing K562 cells and human erythroid precursor cells (ErPCs) derived from neonatal cord blood, the study tested Rg1 at different concentrations. We measured its effects on γ-globin mRNA levels and HbF expression, alongside assessments of cell proliferation and differentiation. In K562 cells, Rg1 at 400 μM significantly increased γ-globin mRNA expression by 4.24 ± 1.08-fold compared to the control. In ErPCs, the 800 μM concentration was most effective, leading to an over 80% increase in F-cells and a marked upregulation in HbF expression. Notably, Rg1 did not adversely affect cell proliferation or differentiation, with the 200 μM concentration showing an increase in γ-globin mRNA by 2.33 ± 0.58-fold, and the 800 μM concentration enhancing HbF expression by 2.59 ± 0.03-fold in K562 cells. Our results underscore Rg1's potential as an effective and safer alternative for β-thalassemia treatment. By significantly enhancing HbF levels without cytotoxicity, Rg1 offers a notable advantage over traditional treatments like Hydroxyurea. While promising, these in vitro findings warrant further in vivo exploration to confirm Rg1's therapeutic efficacy and to unravel its underlying mechanistic pathways.

Effects of Mithramycin on BCL11A Gene Expression and on the Interaction of the BCL11A Transcriptional Complex to γ-Globin Gene Promoter Sequences

The anticancer drug mithramycin (MTH), has been proposed for drug repurposing after the finding that it is a potent inducer of fetal hemoglobin (HbF) production in erythroid precursor cells (ErPCs) from β-thalassemia patients. In this respect, previously published studies indicate that MTH is very active in inducing increased expression of γ-globin genes in erythroid cells. This is clinically relevant, as it is firmly established that HbF induction is a valuable approach for the therapy of β-thalassemia and for ameliorating the clinical parameters of sickle-cell disease (SCD). Therefore, the identification of MTH biochemical/molecular targets is of great interest. This study is inspired by recent robust evidence indicating that the expression of γ-globin genes is controlled in adult erythroid cells by different transcriptional repressors, including Oct4, MYB, BCL11A, Sp1, KLF3 and others. Among these, BCL11A is very important. In the present paper we report evidence indicating that alterations of BCL11A gene expression and biological functions occur during MTH-mediated erythroid differentiation. Our study demonstrates that one of the mechanisms of action of MTH is a down-regulation of the transcription of the BCL11A gene, while a second mechanism of action is the inhibition of the molecular interactions between the BCL11A complex and specific sequences of the γ-globin gene promoter.

The Long Scientific Journey of Sirolimus (Rapamycin): From the Soil of Easter Island (Rapa Nui) to Applied Research and Clinical Trials on β-Thalassemia and Other Hemoglobinopathies

In this review article, we present the fascinating story of rapamycin (sirolimus), a drug able to induce γ-globin gene expression and increased production of fetal hemoglobin (HbF) in erythroid cells, including primary erythroid precursor cells (ErPCs) isolated from β-thalassemia patients. For this reason, rapamycin is considered of great interest for the treatment of β-thalassemia. In fact, high levels of HbF are known to be highly beneficial for β-thalassemia patients. The story of rapamycin discovery began in 1964, with METEI, the Medical Expedition to Easter Island (Rapa Nui). During this expedition, samples of the soil from different parts of the island were collected and, from this material, an antibiotic-producing microorganism (Streptomyces hygroscopicus) was identified. Rapamycin was extracted from the mycelium with organic solvents, isolated, and demonstrated to be very active as an anti-bacterial and anti-fungal agent. Later, rapamycin was demonstrated to inhibit the in vitro cell growth of tumor cell lines. More importantly, rapamycin was found to be an immunosuppressive agent applicable to prevent kidney rejection after transplantation. More recently, rapamycin was found to be a potent inducer of HbF both in vitro using ErPCs isolated from β-thalassemia patients, in vivo using experimental mice, and in patients treated with this compound. These studies were the basis for proposing clinical trials on β-thalassemia patients.

Combined approaches for increasing fetal hemoglobin (HbF) and de novo production of adult hemoglobin (HbA) in erythroid cells from β-thalassemia patients: treatment with HbF inducers and CRISPR-Cas9 based genome editing

Genome editing (GE) is one of the most efficient and useful molecular approaches to correct the effects of gene mutations in hereditary monogenetic diseases, including β-thalassemia. CRISPR-Cas9 gene editing has been proposed for effective correction of the β-thalassemia mutation, obtaining high-level "de novo" production of adult hemoglobin (HbA). In addition to the correction of the primary gene mutations causing β-thalassemia, several reports demonstrate that gene editing can be employed to increase fetal hemoglobin (HbF), obtaining important clinical benefits in treated β-thalassemia patients. This important objective can be achieved through CRISPR-Cas9 disruption of genes encoding transcriptional repressors of γ-globin gene expression (such as BCL11A, SOX6, KLF-1) or their binding sites in the HBG promoter, mimicking non-deletional and deletional HPFH mutations. These two approaches (β-globin gene correction and genome editing of the genes encoding repressors of γ-globin gene transcription) can be, at least in theory, combined. However, since multiplex CRISPR-Cas9 gene editing is associated with documented evidence concerning possible genotoxicity, this review is focused on the possibility to combine pharmacologically-mediated HbF induction protocols with the "de novo" production of HbA using CRISPR-Cas9 gene editing.

Effects of Sirolimus treatment on patients with β-Thalassemia: Lymphocyte immunophenotype and biological activity of memory CD4+ and CD8+ T cells

Inhibitors of the mammalian target of rapamycin (mTOR) have been proposed to improve vaccine responses, especially in the elderly. Accordingly, testing mTOR inhibitors (such as Sirolimus) and other geroprotective drugs might be considered a key strategy to improve overall health resilience of aged populations. In this respect, Sirolimus (also known as rapamycin) is of great interest, in consideration of the fact that it is extensively used in routine therapy and in clinical studies for the treatment of several diseases. Recently, Sirolimus has been considered in laboratory and clinical studies aimed to find novel protocols for the therapy of hemoglobinopathies (e.g. β-Thalassemia). The objective of the present study was to analyse the activity of CD4⁺ and CD8⁺ T cells in β-Thalassemia patients treated with Sirolimus, taking advantages from the availability of cellular samples of the NCT03877809 clinical trial. The approach was to verify IFN-γ releases following stimulation of peripheral blood mononuclear cells (PBMCs) to stimulatory CEF and CEFTA peptide pools, stimulatory for CD4⁺ and CD8⁺ T cells, respectively. The main results of the present study are that treatment of β-Thalassemia patients with Sirolimus has a positive impact on the biological activity and number of memory CD4⁺ and CD8⁺ T cells releasing IFN-γ following stimulation with antigenic stimuli present in immunological memory. These data are to our knowledge novel and in our opinion of interest, in consideration of the fact that β-Thalassemia patients are considered prone to immune deficiency.

The rs368698783 (G>A) Polymorphism Affecting LYAR Binding to the Aγ-Globin Gene Is Associated with High Fetal Hemoglobin (HbF) in β-Thalassemia Erythroid Precursor Cells Treated with HbF Inducers

The human homologue of mouse Ly-1 antibody reactive clone protein (LYAR) is a putative novel regulator of γ-globin gene transcription. The LYAR DNA-binding motif (5′-GGTTAT-3′) is located within the 5′-UTR of the Aγ-globin gene. The LYAR rs368698783 (G>A) polymorphism is present in β-thalassemia patients and decreases the LYAR binding efficiency to the Aγ-globin gene. The objective of this study was to stratify β-thalassemia patients with respect to the rs368698783 (G>A) polymorphism and to verify whether their erythroid precursor cells (ErPCs) differentially respond in vitro to selected fetal hemoglobin (HbF) inducers. The rs368698783 (G>A) polymorphism was detected by DNA sequencing, hemoglobin production by HPLC, and accumulation of globin mRNAs by RT-qPCR. We found that the LYAR rs368698783 (G>A) polymorphism is associated with high basal and induced production of fetal hemoglobin in β-thalassemia patients. The most striking association was found using rapamycin as an HbF inducer. The results presented here could be considered important not only for basic biomedicine but also in applied translational research for precision medicine in personalized therapy of β-thalassemia. Accordingly, our data suggest that the rs368698783 polymorphism might be considered among the parameters useful to recruit patients with the highest probability of responding to in vivo hydroxyurea (HU) treatment.

Expression of γ-globin genes in β-thalassemia patients treated with sirolimus: results from a pilot clinical trial (Sirthalaclin)

Introduction:

β-thalassemia is caused by autosomal mutations in the β-globin gene, which induce the absence or low-level synthesis of β-globin in erythroid cells. It is widely accepted that a high production of fetal hemoglobin (HbF) is beneficial for patients with β-thalassemia. Sirolimus, also known as rapamycin, is a lipophilic macrolide isolated from a strain of Streptomyces hygroscopicus that serves as a strong HbF inducer in vitro and in vivo. In this study, we report biochemical, molecular, and clinical results of a sirolimus-based NCT03877809 clinical trial (a personalized medicine approach for β-thalassemia transfusion-dependent patients: testing sirolimus in a first pilot clinical trial, Sirthalaclin).

Methods:

Accumulation of γ-globin mRNA was analyzed using reverse-transcription quantitative polymerase chain reaction (PCR), while the hemoglobin pattern was analyzed using high-performance liquid chromatography (HPLC). The immunophenotype was analyzed using a fluorescence-activated cell sorter (FACS), with antibodies against CD3, CD4, CD8, CD14, CD19, CD25 (for analysis of peripheral blood mononuclear cells), or CD71 and CD235a (for analysis of in vitro cultured erythroid precursors).

Results:

The results were obtained in eight patients with the β⁺/β⁺ and β⁺/β⁰ genotypes, who were treated with a starting dosage of 1 mg/day sirolimus for 24–48 weeks. The first finding of this study was that the expression of γ-globin mRNA increased in the blood and erythroid precursor cells isolated from β-thalassemia patients treated with low-dose sirolimus. This trial also led to the important finding that sirolimus influences erythropoiesis and reduces biochemical markers associated with ineffective erythropoiesis (excess free α-globin chains, bilirubin, soluble transferrin receptor, and ferritin). A decrease in the transfusion demand index was observed in most (7/8) of the patients. The drug was well tolerated, with minor effects on the immunophenotype, and an only side effect of frequently occurring stomatitis.

Conclusion:

The data obtained indicate that low doses of sirolimus modify hematopoiesis and induce increased expression of γ-globin genes in a subset of patients with β-thalassemia. Further clinical trials are warranted, possibly including testing of the drug in patients with less severe forms of the disease and exploring combination therapies.

Possible effects of sirolimus treatment on the long‑term efficacy of COVID‑19 vaccination in patients with β‑thalassemia: A theoretical perspective

The pandemic caused by the severe acute respiratory syndrome coronavirus (SARS‑CoV‑2), responsible for coronavirus disease 2019 (COVID‑19) has posed a major challenge for global health. In order to successfully combat SARS‑CoV‑2, the development of effective COVID‑19 vaccines is crucial. In this context, recent studies have highlighted a high COVID‑19 mortality rate in patients affected by β‑thalassemia, probably due to their co‑existent immune deficiencies. In addition to a role in the severity of SARS‑CoV‑2 infection and in the mortality rate of COVID‑19‑infected patients with thalassemia, immunosuppression is expected to deeply affect the effectivity of anti‑COVID‑19 vaccines. In the context of the interplay between thalassemia‑associated immunosuppression and the effectiveness of COVID‑19 vaccines, the employment of immunomodulatory molecules is hypothesized. For instance, short‑term treatment with mammalian target of rapamycin inhibitors (such as everolimus and sirolimus) has been found to improve responses to influenza vaccination in adults, with benefits possibly persisting for a year following treatment. Recently, sirolimus has been considered for the therapy of hemoglobinopathies (including β‑thalassemia). Sirolimus induces the expression of fetal hemoglobin (and this may contribute to the amelioration of the clinical parameters of patients with β‑thalassemia) and induces autophagy (thereby reducing the excessive levels of α‑globin). It may also finally contribute to the mobilization of erythroid cells from the bone marrow (thereby reducing anemia). In the present study, the authors present the hypothesis that sirolimus treatment, in addition to its beneficial effects on erythroid‑related parameters, may play a crucial role in sustaining the effects of COVID‑19 vaccination in patients with β‑thalassemia. This hypothesis is based on several publications demonstrating the effects of sirolimus treatment on the immune system.

Treatment of Erythroid Precursor Cells from β-Thalassemia Patients with Cinchona Alkaloids: Induction of Fetal Hemoglobin Production

β-thalassemias are among the most common inherited hemoglobinopathies worldwide and are the result of autosomal mutations in the gene encoding β-globin, causing an absence or low-level production of adult hemoglobin (HbA). Induction of fetal hemoglobin (HbF) is considered to be of key importance for the development of therapeutic protocols for β-thalassemia and novel HbF inducers need to be proposed for pre-clinical development. The main purpose on this study was to analyze Cinchona alkaloids (cinchonidine, quinidine and cinchonine) as natural HbF-inducing agents in human erythroid cells. The analytical methods employed were Reverse Transcription quantitative real-time PCR (RT-qPCR) (for quantification of γ-globin mRNA) and High Performance Liquid Chromatography (HPLC) (for analysis of the hemoglobin pattern). After an initial analysis using the K562 cell line as an experimental model system, showing induction of hemoglobin and γ-globin mRNA, we verified whether the two more active compounds, cinchonidine and quinidine, were able to induce HbF in erythroid progenitor cells isolated from β-thalassemia patients. The data obtained demonstrate that cinchonidine and quinidine are potent inducers of γ-globin mRNA and HbF in erythroid progenitor cells isolated from nine β-thalassemia patients. In addition, both compounds were found to synergize with the HbF inducer sirolimus for maximal production of HbF. The data obtained strongly indicate that these compounds deserve consideration in the development of pre-clinical approaches for therapeutic protocols of β-thalassemia.

Revisiting fetal hemoglobin inducers in beta-hemoglobinopathies: a review of natural products, conventional and combinatorial therapies

Beta-hemoglobinopathies exhibit a heterogeneous clinical picture with varying degrees of clinical severity. Pertaining to the limited treatment options available, where blood transfusion still remains the commonest mode of treatment, pharmacological induction of fetal hemoglobin (HbF) has been a lucrative therapeutic intervention. Till now more than 70 different HbF inducers have been identified. The practical usage of many pharmacological drugs has been limited due to safety concerns. Natural compounds, like Resveratrol, Ripamycin and Bergaptene, with limited cytotoxicity and high efficacy have started capturing the attention of researchers. In this review, we have summarized pharmacological drugs and bioactive compounds isolated from natural sources that have been shown to increase HbF significantly. It primarily discusses recently identified synthetic and natural compounds, their mechanism of action, and their suitable screening platforms, including high throughput drug screening technology and biosensors. It also delves into the topic of combinatorial therapy and drug repurposing for HbF induction. Overall, we aim to provide insights into where we stand in HbF induction strategies for treating β-hemoglobinopathies.

Hemoglobin F (HbF) inducers; History, Structure and Efficacies

Inherited beta-thalassemia is a major disease caused by irregular production of hemoglobin through reducing beta-globin chains. It has been observed that increasing fetal hemoglobin (HbF) production improves symptoms in the patients. Therefore, an increase in the level of HbF has been an operative approach for treating patients with beta-thalassemia. This review represents compounds with biological activities and pharmacological properties that can promote the HBF level and therefore used in the β-thalassemia patients' therapy. Various natural products with different mechanisms of action can be helpful in this medication cure. Clinical trials were efficient in improving the signs of patients. Association of in vivo, and in vitro studies of HbF induction and γ-globin mRNA growth displays that in vitro experiments could be an indicator of the in vivo response. The current study shows that; (a) HbF inducers can be grouped in several classes based on their chemical structures and mechanism of actions; b) According to several clinical trials, well-known drugs such as hydroxyurea and decitabine are useful HbF inducers; (c) The cellular biosensor K562 carrying genes under the control of the human γ-globin and β-globin gene promoters were applied during the researches; d) New natural products and lead compounds were found based on various studies as HbF inducers.

Control of fetal globin expression in man: new opportunities to challenge past discoveries

Decades-old findings supporting origin of F cells in adult life from adult-type progenitors and the in vitro and in vivo enhancement of fetal globin under stress conditions have been juxtaposed against recent mechanistic underpinnings. An updated molecular interrogation did not debunk prior conclusions on the origin of F cells. Although fetal globin reactivation by widely diverse approaches in vitro and in response to anemic stresses in vivo is a work in progress, accumulating evidence converges toward an integrated stress response pathway. The newly uncovered developmental regulators of globin gene switching not only have provided answers to the long-awaited quest of transregulation of switching, they are also reaching a clinical threshold. Although the effect of fetal globin silencers has been robustly validated in adult cells, the response of cells at earlier developmental stages has been unclear and inadequately studied.

Indole derivatives as multifunctional drugs: Synthesis and evaluation of antioxidant, photoprotective and antiproliferative activity of indole hydrazones

Two series of indole derivatives 4-17, 20-22 were easily prepared and assayed for their radical-scavenging ability. Arylidene-1H-indole-2-carbohydrazones showed different extent antioxidant activity in DPPH, FRAP and ORAC assays. Good antioxidant activity is related to the number and position of hydroxyl groups on the arylidene moiety as well as to the presence of methoxy or 4-(diethylamino) group. On the contrary low antioxidant activity is showed by the isomeric 1H-indol-2-yl(methylene)-benzohydrazides. Furthermore, hydrazones 4-17 showed photoprotective capacities with satisfactory in vitro SPF as compared to the commercial PBSA sunscreen filter. The indole 16 and 17, showing the best antioxidant and photoprotective profile, were included in different formulation and their topical release was evaluated. Varying the formulation composition, it was possible to optimize skin adsorption and solubility of the active indole in the formulation. The antiproliferative effect of the hydrazones 4-17 was tested on human erythroleukemia K562 and melanoma Colo-38 cells. Hydrazones 11, 16 and 17 showed growth inhibition at sub micromolar concentrations on both cell lines. These results indicate indole hydrazones as potential multifunctional molecules especially in the treatment of neoplastic diseases being the good antioxidant properties of 16 and 17 correlated to their high antiproliferative activity.

Benzofuran hydrazones as potential scaffold in the development of multifunctional drugs: Synthesis and evaluation of antioxidant, photoprotective and antiproliferative activity

New benzofuranhydrazones 3-12 were easily prepared and assayed for their radical-scavenging ability. Hydrazones 3-12 showed different extent antioxidant activity in DPPH, FRAP and ORAC assays. Good antioxidant activity is related to the number and position of hydroxyl groups on the arylidene moiety. High antioxidant activity is showed by the 2-hydroxy-4-(diethylamino)benzylidene derivative 11. Furthermore, hydrazones 3-12 showed photoprotective capacities with satisfactory in vitro SPF as compared to the commercial PBSA sunscreen filter. The antiproliferative effects of the hydrazones 3-12 was tested on erythroleukemia K562 and Colo-38 melanoma human cells. All the compounds showed growth inhibition in the micromolar to sub micromolar concentration range. If taken together these results points to benzofuran hydrazones as potential multifunctional molecules especially in the treatment of neoplastic diseases being the good antioxidant properties of 5, 7 and 11 correlated to their high antiproliferative activity.

Bis(dimethylsulfoxide)carbonateplatinum(ii), a new synthon for a low-impact, versatile synthetic route to anticancer Pt carboxylates

The work describes a new low-impact synthetic route to Pt(ii)-carboxylate complexes, a class of compounds provided with established anticancer activity. The process is based on the ligand substitution on [PtCO3(Me2SO-S)2] (), a new synthon that can be easily prepared in water with high yield, is stable as a solid, and is reactive in solution where all its ligands can be easily replaced. It reacts with acidic O-donors releasing CO2 as the only side-product, whose development also supplies a driving force toward the products. The substitution of carbonate led to new Pt-DMSO carboxylate complexes , while the total substitution of the ligands of complex gave new Pt-phosphino carboxylates in high yields. The X-ray crystal structures of complexes [Pt(d(-)-quinate-O,O')(Me2SO-S)2] (), [Pt(salicylate)(Me2SO-S)2] () and [Pt(salicylate)(PPh3)2] () were determined. The tests of the antiproliferative activity of complexes on two human tumoral cell lines, A2780 (cisplatin-sensitive) and SKOV-3 (cisplatin-resistant), showed that the PTA (PTA = 1,3,5-triaza-7-phosphaadamantane) complexes were the most active on both cell lines.

Recent trends in the gene therapy of β-thalassemia

The β-thalassemias are a group of hereditary hematological diseases caused by over 300 mutations of the adult β-globin gene. Together with sickle cell anemia, thalassemia syndromes are among the most impactful diseases in developing countries, in which the lack of genetic counseling and prenatal diagnosis have contributed to the maintenance of a very high frequency of these genetic diseases in the population. Gene therapy for β-thalassemia has recently seen steadily accelerating progress and has reached a crossroads in its development. Presently, data from past and ongoing clinical trials guide the design of further clinical and preclinical studies based on gene augmentation, while fundamental insights into globin switching and new technology developments have inspired the investigation of novel gene-therapy approaches. Moreover, human erythropoietic stem cells from β-thalassemia patients have been the cellular targets of choice to date whereas future gene-therapy studies might increasingly draw on induced pluripotent stem cells. Herein, we summarize the most significant developments in β-thalassemia gene therapy over the last decade, with a strong emphasis on the most recent findings, for β-thalassemia model systems; for β-, γ-, and anti-sickling β-globin gene addition and combinatorial approaches including the latest results of clinical trials; and for novel approaches, such as transgene-mediated activation of γ-globin and genome editing using designer nucleases.

Erythroid induction of K562 cells treated with mithramycin is associated with inhibition of raptor gene transcription and mammalian target of rapamycin complex 1 (mTORC1) functions

Rapamycin, an inhibitor of mTOR activity, is a potent inducer of erythroid differentiation and fetal hemoglobin production in β-thalassemic patients. Mithramycin (MTH) was studied to see if this inducer of K562 differentiation also operates through inhibition of mTOR. We can conclude from the study that the mTOR pathway is among the major transcript classes affected by mithramycin-treatment in K562 cells and a sharp decrease of raptor protein production and p70S6 kinase is detectable in mithramycin treated K562 cells. The promoter sequence of the raptor gene contains several Sp1 binding sites which may explain its mechanism of action. We hypothesize that the G + C-selective DNA-binding drug mithramycin is able to interact with these sequences and to inhibit the binding of Sp1 to the raptor promoter due to the following results: (a) MTH strongly inhibits the interactions between Sp1 and Sp1-binding sites of the raptor promoter (studied by electrophoretic mobility shift assays, EMSA); (b) MTH strongly reduces the recruitment of Sp1 transcription factor to the raptor promoter in intact K562 cells (studied by chromatin immunoprecipitation experiments, ChIP); (c) Sp1 decoy oligonucleotides are able to specifically inhibit raptor mRNA accumulation in K562 cells. In conclusion, raptor gene expression is involved in mithramycin-mediated induction of erythroid differentiation of K562 cells and one of its mechanism of action is the inhibition of Sp1 binding to the raptor promoter.

RAD001-mediated STAT3 upregulation and megakaryocytic differentiation

RAD001 is currently used as an immunosuppressant and anticancer drug. Megakaryocyte (MK) differentiation includes development from pluripotent stem cells to proliferation and differentiation toward MK formation and platelet maturation. Our preliminary assay showed that RAD001 might stimulate MK differentiation; however, the exact regulatory mechanisms needed to be elucidated. By the ex vivo assay, RAD001 induced MK differentiation in human haematopoietic stem cells, with both the stimulation of CFU-GM colony formation and CD61 surface marker expression. Then, BALB/c mice were orally administrated with or without agrylin and/or RAD001 for 15 days. The platelet count and bone marrow CFU-MK colony formation were eliminated by agrylin, but unchanged in RAD001 and RAD001 plus agrylin mice. An ex vivo assay of bone marrow-derived stem cells demonstrated that RAD001 increased the number of CFU-MK colonies. The MK count in bone section indicated the decreased effect by agrylin and then recovered by RAD001. The level of plasma thrombopoietin was also enhanced in RAD001-treated mice. The effect of RAD001 on human leukaemic K562 and HEL cells showed the growth inhibition and MK differentiation activities; including morphological observation, CD41 and CD61 expression, and platelet factor 4 secretion. In RAD001-treated HEL cells, p-STAT3 expression, STAT3 translocation, and STAT3-DNA binding activity were up-regulated. Furthermore, STAT3 siRNA decreased the p-STAT3 and CD61 expression, as well as the CD61 fluorescence intensity, indicating that STAT3 may be critical in RAD001-mediated MK differentiation. Conclusion, the present study demonstrated that RAD001 might have the capacity to induce MK differentiation through the up-regulation of STAT3 signalling.

A combined approach for β-thalassemia based on gene therapy-mediated adult hemoglobin (HbA) production and fetal hemoglobin (HbF) induction

Gene therapy might fall short in achieving a complete reversion of the β-thalassemic phenotype due to current limitations in vector design and myeloablative regimen. Following gene transfer, all or a large proportion of erythroid cells might express suboptimal levels of β-globin, impairing the therapeutic potential of the treatment. Our aim was to evaluate whether, in absence of complete reversion of the β-globin phenotype upon gene transfer, it is possible to use fetal hemoglobin induction to eliminate the residual α-globin aggregates and achieve normal levels of hemoglobin. Transgenic K562 cell lines and erythroid precursor cells from β⁰39-thalassemia patients were employed. Gene therapy was performed with the lentiviral vector T9W. Induction of fetal hemoglobin was obtained using mithramycin. Levels of mRNA and hemoglobins were determined by qRT-PCR and HPLC. First, we analyzed the effect of mithramycin on K562 transgenic cell lines harboring different copies of a lentiviral vector carrying the human β-globin gene, showing that γ-globin mRNA expression and HbF production can be induced in the presence of high levels of β-globin gene expression and HbA accumulation. We then treated erythroid progenitor cells from β-thalassemic patients with T9W, which expresses the human β-globin gene and mithramycin separately or in combination. When transduction with our lentiviral vector is insufficient to completely eliminate the unpaired α-globin chains, combination of β-globin gene transfer therapy together with fetal hemoglobin induction might be very efficacious to remove the excess of α-globin proteins in thalassemic erythroid progenitor cells.

C(5) modified uracil derivatives showing antiproliferative and erythroid differentiation inducing activities on human chronic myelogenous leukemia K562 cells

The K562 cell line has been proposed as a useful experimental system to identify anti-tumor compounds acting by inducing terminal erythroid differentiation. K562 cells exhibit a low proportion of hemoglobin-synthesizing cells under standard cell growth conditions, but are able to undergo terminal erythroid differentiation when treated with a variety of anti-tumor compounds. In this paper we report a screening study on a set of different modified C(5) uracil derivatives for the evaluation of their antiproliferative effect in connection with erythroid differentiation pathways, and for defining a new class of drug candidates for the treatment of chronic myelogenous leukemia. Activity of the derivatives tested can be classified in two effect: an antiproliferative effect linked to a high level of erythroid differentiation activity and an antiproliferative effect without activation of gamma globin genes The highest antiproliferative effect and erythroid induction was shown by compound 9, a thymine derivative bearing a n-octyl chain on nitrogen N(1), whereas thymine did not show any effect, suggesting the importance of the linear alkyl chain in position N(1). To our knowledge this compound should be considered among the most efficient inducers of erythroid differentiation of K562 cells. This work is the starting point for the quest of more effective and specific drugs for the induction of terminal erythroid differentiation, for leading new insights in the treatment of neoplastic diseases with molecules acting by inducing differentiation rather than by simply exerting cytotoxic effects.

Mammalian target of rapamycin (mTOR) inhibitors: potential uses and a review of haematological adverse effects

Mammalian target of rapamycin (mTOR) inhibitors (mTORis) constitute a relatively new category of immunosuppressive and antineoplastic drugs. These share a unique mechanism of action that is focused on the inhibition of the mTOR. Their clinical applications have recently expanded significantly to cover a wide spectrum of immune and non-immune-mediated disorders, including, apart from solid organ transplantation, various solid organ and haematological malignancies, rheumatological and auto-immune diseases such as rheumatoid arthritis, systemic lupus erythematosus, fibrotic conditions, e.g. pulmonary and hepatic fibrosis, and even metabolic problems such as diabetes mellitus and obesity. The most challenging and frequent adverse effects of the mTORis are the haematological ones, especially anaemia, leukopenia and thrombocytopenia. A unique characteristic of mTORi-induced anaemia is concurrent marked microcytosis. Recently, mechanisms have been proposed to explain the microcytic appearance of this anaemia; these include globin production defect, erythropoietin resistance, chronic inflammation, dysregulation of cellular iron metabolism and hepcidin-mediated iron homeostasis interference. As the differential diagnosis of microcytic anaemia includes pure iron deficiency, functional iron deficiency and haemoglobinopathies, characterization of the anaemia requires significant investigation, time and costs. Therefore, understanding of the likely interaction between mTORis and patients is valuable in clinical practice. Moreover, this could expand the drugs' therapeutic applications to other disorders, and suggest novel targets for further research.

Mammalian target of rapamycin (mTOR) inhibitors: potential uses and a review of haematological adverse effects

Mammalian target of rapamycin (mTOR) inhibitors (mTORis) constitute a relatively new category of immunosuppressive and antineoplastic drugs. These share a unique mechanism of action that is focused on the inhibition of the mTOR. Their clinical applications have recently expanded significantly to cover a wide spectrum of immune and non-immune-mediated disorders, including, apart from solid organ transplantation, various solid organ and haematological malignancies, rheumatological and auto-immune diseases such as rheumatoid arthritis, systemic lupus erythematosus, fibrotic conditions, e.g. pulmonary and hepatic fibrosis, and even metabolic problems such as diabetes mellitus and obesity. The most challenging and frequent adverse effects of the mTORis are the haematological ones, especially anaemia, leukopenia and thrombocytopenia. A unique characteristic of mTORi-induced anaemia is concurrent marked microcytosis. Recently, mechanisms have been proposed to explain the microcytic appearance of this anaemia; these include globin production defect, erythropoietin resistance, chronic inflammation, dysregulation of cellular iron metabolism and hepcidin-mediated iron homeostasis interference. As the differential diagnosis of microcytic anaemia includes pure iron deficiency, functional iron deficiency and haemoglobinopathies, characterization of the anaemia requires significant investigation, time and costs. Therefore, understanding of the likely interaction between mTORis and patients is valuable in clinical practice. Moreover, this could expand the drugs' therapeutic applications to other disorders, and suggest novel targets for further research.

Erythroid induction of chronic myelogenous leukemia K562 cells following treatment with a photoproduct derived from the UV-A irradiation of 5-methoxypsoralen

Induction of terminal erythroid differentiation can be an efficient strategy to inhibit proliferation of chronic myelogenous leukemia cells. Psoralens, well-known photo-chemotherapeutic agents, were found to be efficient at inducing erythroid differentiation of K562 cells, an in vitro cell line isolated from the pleural effusion of a patient with chronic myelogenous leukemia in blast crisis. The effects of crude pre-irradiated solutions of 5-methoxypsoralen on erythroid differentiation of human leukemic K-562 cells were evaluated. The major photoproduct was characterized and analyzed, and it was found to induce erythroid differentiation of K562 cells and inhibit NF-kappaB/DNA interactions.

[Effects of Chinese herbal medicine Yiqi Huoxue Formula on TGF-β/smad signal transduction pathway and connective tissue growth factor in rats with renal interstitial fibrosis]

OBJECTIVE

To observe the effects of Yiqi Huoxue Formula (YQHXF), a compound Chinese herbal medicine, on transforming growth factor-β (TGF-β)/smad signal transduction pathway and connective tissue growth factor (CTGF) in rats with renal interstitial fibrosis

METHODS

Unilateral ureteral obstruction (UUO) rat model was established and the rats were randomly divided into 5 groups: untreated group, high-, medium-, and low-dose YQHXF groups and fosinopril sodium group. Another group with sham operation was set as control. All rats were administered with corresponding drugs for 3 weeks. After the last administration, each rat was sacrificed and weighed and the serum was separated for creatinine (Cr) and blood urea nitrogen (BUN) detection. Kidneys of the rats were taken out, and mRNA and protein expressions of TGF-β, smad2, smad7 and CTGF were measured with real-time fluorescent quantitative reverse transcription-polymerase chain reaction and Western blotting respectively; fibrosis of the kidney tissue was observed with hematoxylin-eosin (HE) staining and Masson trichrome staining.

RESULTS

Compared with sham-operation group, Cr and BUN in serum of UUO groups were increased, while high-dose YQHXF treatment decreased the UUO-induced increase of Cr and BUN levels. HE staining and Masson staining results showed that the renal tubular epithelial cells in untreated group got atrophied; lumens of renal tubules expanded; fibroplastic proliferation and inflammatory cell infiltration were observed in renal interstitium; the number of glomerulus decreased and collagen increased significantly compared with sham-operation group. In the high- and medium-dose YQHXF groups and fosinopril sodium group, the histopathological changes of inflammatory cell infiltration, fibroplastic proliferation, expansion of lumens of renal tubules was improved as compared with the untreated group. The mRNA and protein expressions of TGF-β, smad2 and CTGF in untreated group were higher than those in sham-operation group (P<0.05), and the mRNA and protein expressions of smad7 in untreated group were lower than those in the sham-operation group (P<0.05). Compared with untreated group, high- and medium-dose of YQHXF significantly down-regulated the mRNA and protein expressions of TGF-β, smad2 and CTGF (P<0.01, P<0.05), and up-regulated the mRNA and protein expressions of smad7 (P<0.01, P<0.05).

CONCLUSIONS

The mRNA expression of CTGF in UUO rats may be regulated by TGF-β/smad signaling transduction pathway. YQHXF might inhibit the expression of CTGF through down-regulation of TGF-β and smad2 and up-regulation of smad7, thus inhibiting the progression of renal interstitial fibrosis.

Effects of biomaterials for Lab-on-a-chip production on cell growth and expression of differentiated functions of leukemic cell lines

The rapid increase of the applications for Lab-on-a-chip devices has attracted the interest of researchers and engineers on standard process of the electronics industry for low production costs and large scale development, necessary for disposable applications. The printed circuit board technology could be used for this purpose, in particular for the wide range of materials available. In this paper, assays on biocompatibility of materials used for Lab-on-a-chip fabrication has been carried out using two tumor cell lines growing in suspension, the human chronic myelogenous leukemia K562 cell line, able to undergo erythroid differentiation when cultured with chemical inducers, and the lymphoblastoid cell line (LCL), extensively used for screening of cytotoxic T-lymphocytes (CTLs). We have demonstrated that some materials strongly inhibit cell proliferation of both the two cell lines to an extent higher that 70-75%, but only after a prolonged exposure of 3-6 days (Copper, Gold over Nickel, Aramid fiber filled epoxy uncured, b-stage epoxy die attach film, Tesa 4985 adhesive tape, Pyralux uncured, Copper + 1-octodecanethiol). However, when experiments were performed with short incubation time (1 h), only Aramid fiber filled epoxy uncured was cytotoxic. Variation of the results concerning the other materials was appreciable when the experiments performed on two cell lines were compared together. Furthermore, the effects of the materials on erythroid differentiation and CTL-mediated LCL lysis confirmed, in most of the cases, the data obtained in cytotoxic and antiproliferative tests.

Effects of Astragalus polysaccharide on the erythroid lineage and microarray analysis in K562 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Astragalus polysaccharide (APS), obtained from Astragalus membranaceus, displays a range of activities in many systems, including the promotion of immune responses, anti-inflammation, and the protection of vessels. It possesses potent pharmacological activity on differentiation to the erythroid lineage.

AIM OF THE STUDY

To investigate the effects of APS on the erythroid differentiation and the mechanism of action by microarray analysis in K562 cells.

MATERIALS AND METHODS

Benzidine staining, semi-quantitative RT-PCR, Western blot and microarray methods were used to survey the effects of APS on inducing erythroid differentiation and the changes of gene expression profile in K562 cells.

RESULTS

Of the 13.2% positive cells detected by benzidine staining, the induction was the highest with 200 microg/ml APS on 72h. Ggamma-mRNA expression and fetal hemoglobin synthesis were significantly up-regulated. Microarray analysis showed that 31 genes were up-regulated and 108 genes were down-regulated. These differential expression genes generally regulate protein binding, cellular metabolic process, the cell proliferation, and transcriptional activator activity. The gamma-globin gene was up-regulated, the genes related with erythroid differentiation such as LMO2, Runx1 and GTF2I were up-regulated, while Bklf, Eklf, EPHB4 and Sp1 were down-regulated.

CONCLUSIONS

Our studies indicate that APS indicate potent activities on the erythroid differentiation by modulating genes of LMO2, Klf1, Klf3, Runx1, EphB4 and Sp1, increasing gamma-globin mRNA expression and fetal hemoglobin synthesis in K562 cells.

Production of beta-globin and adult hemoglobin following G418 treatment of erythroid precursor cells from homozygous beta(0)39 thalassemia patients

In several types of thalassemia (including beta(0)39-thalassemia), stop codon mutations lead to premature translation termination and to mRNA destabilization through nonsense-mediated decay. Drugs (for instance aminoglycosides) can be designed to suppress premature termination, inducing a ribosomal readthrough. These findings have introduced new hopes for the development of a pharmacologic approach to the cure of this disease. However, the effects of aminoglycosides on globin mRNA carrying beta-thalassemia stop mutations have not yet been investigated. In this study, we have used a lentiviral construct containing the beta(0)39-thalassemia globin gene under control of the beta-globin promoter and a LCR cassette. We demonstrated by fluorescence-activated cell sorting (FACS) analysis the production of beta-globin by K562 cell clones expressing the beta(0)39-thalassemia globin gene and treated with G418. More importantly, after FACS and high-performance liquid chromatography (HPLC) analyses, erythroid precursor cells from beta(0)39-thalassemia patients were demonstrated to be able to produce beta-globin and adult hemoglobin after treatment with G418. This study strongly suggests that ribosomal readthrough should be considered a strategy for developing experimental strategies for the treatment of beta(0)-thalassemia caused by stop codon mutations. Am. J. Hematol., 2009. (c) 2009 Wiley-Liss, Inc.

Increase in gamma-globin mRNA content in human erythroid cells treated with angelicin analogs

The aim of the present study was to identify molecular analogs of angelicin (ANG) able to increase erythroid differentiation of K562 cells and expression of gamma-globin genes in human erythroid precursor cells, with low effects on apoptosis. ANG-like molecules are well-known photosensitizers largely used for their antiproliferative activity in the treatment of different skin diseases (i.e., psoriasis, vitiligo, eczema, and mycosis fungoides). To verify the activity of these derivatives, we employed three experimental cell systems: (1) the human leukemic K562 cell line, (2) K562 cell clones stably transfected with a pCCL construct carrying green-EGFP under the gamma-globin gene promoter, and (3) the two-phase liquid culture of human erythroid progenitors isolated from normal donors and beta-thalassemia patients. The results of our study suggest that trimethyl ANG is a powerful inducer of erythroid differentiation, compared with known inducers, such as ANG, cytosine arabinoside, mithramycin, and cisplatin. These data could have practical relevance, because pharmacologically mediated regulation of human gamma-globin gene expression, with the consequent induction of fetal hemoglobin, is considered a potential therapeutic approach in hematological disorders including beta-thalassemia and sickle cell anemia.

Bergamot (Citrus bergamia Risso) fruit extracts as γ-globin gene expression inducers: phytochemical and functional perspectives

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.

A cell stress signaling model of fetal hemoglobin induction: what doesn't kill red blood cells may make them stronger

A major goal of hemoglobinopathy research is to develop treatments that correct the underlying molecular defects responsible for sickle cell disease and beta-thalassemia. One approach to achieving this goal is the pharmacologic induction of fetal hemoglobin (HbF). This strategy is capable of inhibiting the polymerization of sickle hemoglobin and correcting the globin chain imbalance of beta-thalassemia. Despite this promise, none of the currently available HbF-inducing agents exhibit the combination of efficacy, safety, and convenience of use that would make them applicable to most patients. The recent success of targeted drug therapies for malignant diseases suggests that this approach could be effective for developing optimal HbF-inducing agents. A first step in applying this approach is the identification of specific molecular targets. However, while >70 HbF-inducing agents have been described, neither molecular mechanisms nor target molecules have been definitively verified for any of these compounds. To help focus investigation in this area, we have reviewed known HbF-inducing agents and their proposed mechanisms of action. We find that in many cases, current models inadequately explain key experimental results. By integrating features of the erythropoietic stress model of HbF induction with data from recent intracellular signaling experiments, we have developed a new model that has the potential to explain several findings that are inconsistent with previous models and to unify most HbF-inducing agents under a common mechanism: cell stress signaling. If correct, this or related models could lead to new opportunities for development of targeted therapies for the beta-hemoglobinopathies.

Synthesis of glycose carbamides and evaluation of the induction of erythroid differentiation of human erythroleukemic K562 cells

A series of carbamides derived from 1,2:5,6-di-O-isopropylidene-D-gluco- and D-allofuranose as well as their 5,6-O-deprotected analogues (2 and 4) and methyl 3,4-O-isopropylidene-alpha- and beta-D-galactopyranosides (5 and 6) have been prepared in order to evaluate their ability to induce erythroid differentiation of human erythroleukemic K562 cells. Twenty out of 51 carbamides tested exhibit an appreciable activity as inducers of erythroid differentiation and have been fully characterized and described.

A novel frameshift mutation (+A) at codon 18 of the beta-globin gene associated with high persistence of fetal hemoglobin phenotype and deltabeta-thalassemia

We report in this paper a novel thalassemia mutation (insertion of a single A nucleotide within the exon 1, at codon 18, of the beta-globin gene) associated with a deletion of the deltabeta-globin gene region, in a patient exhibiting high persistence of fetal hemoglobin. The novel mutation causes a frameshift with the generation of a UGA stop codon. Analysis of the parent's DNA demonstrates that the A insertion and frameshift mutation are inherited from the father, while the deltabeta-globin gene deletion is inherited from the mother. Gene dosage analysis and deletion-specific PCR demonstrate that the deletion is the (deltabeta)(0) Sicilian deletion, involving a 13.4-kb deltabeta-globin gene region.

Fetal Hemoglobin Inducers from the Natural World: A Novel Approach for Identification of Drugs for the Treatment of {beta}-Thalassemia and Sickle-Cell Anemia

The objective of this review is to present examples of lead compounds identified from biological material (fungi, plant extracts and agro-industry material) and of possible interest in the field of a pharmacological approach to the therapy of beta-thalassemia using molecules able to stimulate production of fetal hemoglobin (HbF) in adults. Concerning the employment of HbF inducers as potential drugs for pharmacological treatment of beta-thalassemia, the following conclusions can be reached: (i) this therapeutic approach is reasonable, on the basis of the clinical parameters exhibited by hereditary persistence of fetal hemoglobin patients, (ii) clinical trials (even if still limited) employing HbF inducers were effective in ameliorating the symptoms of beta-thalassemia patients, (iii) good correlation of in vivo and in vitro results of HbF synthesis and gamma-globin mRNA accumulation indicates that in vitro testing might be predictive of in vivo responses and (iv) combined use of different inducers might be useful to maximize HbF, both in vitro and in vivo. In this review, we present three examples of HbF inducers from the natural world: (i) angelicin and linear psoralens, contained in plant extracts from Angelica arcangelica and Aegle marmelos, (ii) resveratrol, a polyphenol found in grapes and several plant extracts and (iii) rapamycin, isolated from Streptomyces hygroscopicus.

Induction of gamma-globin mRNA, erythroid differentiation and apoptosis in UVA-irradiated human erythroid cells in the presence of furocumarin derivatives

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.