Iron Overload Disease Research Articles

L'acéruléoplasminémie héréditaire, une pathologie à ne pas méconnaître

Aceruloplasminemia is a rare iron-overload disease that should be better known by physicians. It is an autosomal recessive disorder due to mutations in ceruloplasmin gene causing systemic iron overload, including cerebral and liver parenchyma. The impairment of ferroxidase ceruloplasmin activity leads to intracellular iron retention leading aceruloplasminemia symptoms. Neurologic manifestations include cognitive impairment, ataxia, extrapyramidal syndrome, abnormal movements, and psychiatric-like syndromes. Physicians should search for aceruloplasminemia in several situations with high ferritin levels: microcytic anaemia, diabetes mellitus, neurological and psychiatric disorders. Diagnosis approach is based on the study of transferrin saturation and hepatic iron content evaluated by magnetic resonance imaging of the liver. Ceruloplasmin dosage is required in case of low transferrin saturation and high hepatic iron content and genetic testing is mandatory in case of serum ceruloplasmin defect. Neurological manifestations occur in the sixties decade and leads to disability. Iron chelators are widely used. Despite their efficacy on systemic and cerebral iron overload, iron chelators tolerance is poor. Early initiation of iron chelation therapy might prevent or slowdown neurodegeneration, highlighting the need for an early diagnosis but their clinical efficacy remains uncertain.

Synthesis of a new tetradentate chelator with 1-Hydoroxy-2(1H)-pyridinone (HOPO) as chelating unit: Interaction with Fe (III), solution thermodynamics and DFT studies

1,2-Hydroxypyridinone (1,2-HOPO) forms very stable transition metal complexes that may be useful in various ways, among these the iron complexes have been long used for the treatment of iron overload diseases like β-Thalassemia. A new tetradentate chelator, 1-hydroxy-N-[3-[2-[2-[3-[(1-hydroxy-6-oxo-pyridine-2carbonyl)amino]propoxy]ethoxy]ethoxy]propyl]-6-oxo-pyridine-2-carboxamide (L) having two 1,2-HOPO units with long chain amine backbone has been synthesized and characterized through various techniques like TLC, solubility, melting point, FT-IR, 1H NMR, 13C NMR, ESI-MS, UV–Vis and emission spectroscopy. The protonation constants of the ligand were determined by both potentiometrically as well as spectrophotometrically in aqueous medium at 25° ±1 °C. The solution thermodynamics of the ligand its Fe(III) complexes in aqueous solution were also studied. The pKa values for ligand are found to be 7.34 and 6.06 and the formation constant of metal complex (M2L3) is found to be logβ230 = 42.45. To support the experimental data, theoretical calculation at DFT level of theory was done using GGA (Gradient Generalized Approximation) with BLYP functional and DZP basis set. The results of calculated thermodynamic properties suggest that, ΔG follows the same trend of protonation as determined by potentiometry and spectrophotometry. Studies of the DFT optimized structures of LH2, LH− shows that, there is π stacking interaction between the hydroxypyridinone rings in the species and the intramolecular π-stacking interaction decreases as the distance between two pyridine ring increases upon deprotonation and was found to be 2.7, 3.2 and 14.6 Å for LH2, LH− and L−2 respectively.

Potential Mechanisms Underlying the Hepatic-Protective Effects of Danshensu on Iron Overload Mice.

The purpose of the present study was to investigate the protective effects and the underlying mechanisms of Danshensu on liver injury induced by iron overload. The mouse model was induced by injection of iron dextran intraperitoneally for 14 d. Danshensu significantly ameliorated liver injury by decreasing iron accumulation in the liver, possibly by down-regulating the expression of iron uptake-related proteins: divalent metal ion transporters-1 (DMT-1), transferrin receptor (TfR), and L-type calcium channel α1C subunit. Furthermore, Danshensu alleviated oxidative stress injury through potentiating glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities; Immunohistochemistry results demonstrated that Danshensu reduced the expression of inflammatory cytokines: interleukin-6 (IL-6) and transforming growth factor-beta (TGF-β). Moreover, Danshensu prominently inhibited hepatocyte apoptosis through decreasing Bax and Caspase-3 and increasing Bcl-2 expression levels. The present results suggest that Danshensu possess significant hepatic-protection at least partly through inhibition of iron uptake, oxidative stress, inflammatory, and apoptosis. Therefore, we believe that Danshensu could be used as a promising therapeutic agent for preventing and treating iron overload diseases.

A Novel Star Like Eight-Arm Polyethylene Glycol-Deferoxamine Conjugate for Iron Overload Therapy.

The traditional iron chelator deferoxamine (DFO) has been widely used in the treatment of iron overload disease. However, DFO has congenital disadvantages, including a very short circular time and non-negligible toxicity. Herein, we designed a novel multi-arm conjugate for prolonging DFO duration in vivo and reducing cytotoxicity. The star-like 8-arm-polyethylene glycol (8-arm-PEG) was used as the macromolecular scaffold, and DFO molecules were bound to the terminals of the PEG branches via amide bonds. The conjugates displayed comparable iron binding ability to the free DFO. Furthermore, these macromolecule conjugates could significantly reduce the cytotoxicity of the free DFO, and showed satisfactory iron clearance capability in the iron overloaded macrophage RAW 246.7. The plasma half-life of the 8-arm-PEG-DFO conjugate was about 190 times than that of DFO when applied to an intravenously administered rat model. In conclusion, research indicated that these star-like PEG-based conjugates could be promising candidates as long circulating, less toxic iron chelators.

Chronic exposure to excess iron promotes EMT and cancer via p53 loss in pancreatic cancer

Based on the evidence that hemochromatosis, an iron-overload disease, drives hepatocellular carcinoma, we hypothesized that chronic exposure to excess iron, either due to genetic or environmental causes, predisposes an individual to cancer. Using pancreatic cancer as our primary focus, we employed cell culture studies to interrogate the connection between excess iron and cancer, and combined in vitro and in vivo studies to explore the connection further. Ferric ammonium citrate was used as an exogenous iron source. Chronic exposure to excess iron induced epithelial-mesenchymal transition (EMT) in normal and cancer cell lines, loss of p53, and suppression of p53 transcriptional activity evidenced from decreased expression of p53 target genes (p21, cyclin D1, Bax, SLC7A11). To further extrapolate our cell culture data, we generated EL-KrasG12D (EL-Kras) mouse (pancreatic neoplastic mouse model) expressing Hfe+/+and Hfe−/− genetic background. p53 target gene expression decreased in EL-Kras/Hfe−/− mouse pancreas compared to EL-Kras/Hfe+/+ mouse pancreas. Interestingly, the incidence of acinar-to-ductal metaplasia and cystic pancreatic neoplasms (CPN) decreased in EL-Kras/Hfe−/− mice, but the CPNs that did develop were larger in these mice than in EL-Kras/Hfe+/+ mice. In conclusion, these in vitro and in vivo studies support a potential role for chronic exposure to excess iron as a promoter of more aggressive disease via p53 loss and SLC7A11 upregulation within pancreatic epithelial cells.

Extrahepatic deficiency of transferrin receptor 2 is associated with increased erythropoiesis independent of iron overload

Transferrin receptor 2 (TFR2) is a transmembrane protein expressed mainly in hepatocytes and in developing erythroid cells and is an important focal point in systemic iron regulation. Loss of TFR2 function results in a rare form of the iron-overload disease hereditary hemochromatosis. Although TFR2 in the liver has been shown to be important for regulating iron homeostasis in the body, TFR2's function in erythroid progenitors remains controversial. In this report, we analyzed TFR2-deficient mice in the presence or absence of iron overload to distinguish between the effects caused by a high iron load and those caused by loss of TFR2 function. Analysis of bone marrow from TFR2-deficient mice revealed a reduction in the early burst-forming unit-erythroid and an expansion of late-stage erythroblasts that was independent of iron overload. Spleens of TFR2-deficient mice displayed an increase in colony-forming unit-erythroid progenitors and in all erythroblast populations regardless of iron overload. This expansion of the erythroid compartment coincided with increased erythroferrone (ERFE) expression and serum erythropoietin (EPO) levels. Rescue of hepatic TFR2 expression normalized hepcidin expression and the total cell count of the bone marrow and spleen, but it had no effect on erythroid progenitor frequency. On the basis of these results, we propose a model of TFR2's function in murine erythropoiesis, indicating that deficiency in this receptor is associated with increased erythroid development and expression of EPO and ERFE in extrahepatic tissues independent of TFR's role in the liver.

Deferasirox protects against hydrogen peroxide-induced cell apoptosis by inhibiting ubiquitination and degradation of p21WAF1/CIP1

Deferasirox (DFX) is an iron chelator approved for the treatment of iron overload diseases. However, the role of DFX in oxidative stress-induced cell apoptosis and the exact molecular mechanisms underlying these processes remain poorly understood and require further investigation. In this study, we found that DFX rendered resistant to H2O2-induced apoptosis in HEK293T cells, reduced the intracellular levels of the labile iron pool (LIP) and oxidative stress induced by H2O2. Furthermore, DFX inhibited the ubiquitination and degradation of the cyclin-dependent kinase inhibitor p21WAF1/CIP1 (p21) via modulation of the interaction of p21 with SCF-Skp2. DFX also showed the inhibition effect on the activation of c-Jun N-terminal kinase (JNK), pro-caspase-3 and related mitochondrial apoptosis pathway induced by H2O2. These results provide novel insights into the molecular mechanism underpinning iron-mediated oxidative stress and apoptosis, and they may represent a promising target for therapeutic interventions in related pathological conditions.

Diagnosis and Treatment of Alcohol‐Associated Liver Diseases: 2019 Practice Guidance From the American Association for the Study of Liver Diseases

Alcoholic liver disease (ALD) represents a spectrum of liver injury resulting from alcohol use, ranging from hepatic steatosis to more advanced forms including alcoholic hepatitis (AH), alcoholic cirrhosis (AC), and acute alcoholic hepatitis presenting as acute on chronic liver failure (ACLF). ALD is a major cause of liver disease worldwide, both on its own and as a co-factor in the progression of chronic viral hepatitis, nonalcoholic fatty liver disease (NAFLD), iron overload and other liver diseases. ALD develops through several stages, beginning with hepatic steatosis, and, in some individuals, gradually progressing through alcoholic hepatitis (the histological correlate of which is alcoholic steatohepatitis), culminating in cirrhosis (Figure 1). Progression through these various stages is dependent upon continued heavy alcohol consumption and other risk factors, including female sex, genetic susceptibility, diet, and comorbid liver disease. ALD carries a significant stigma in society. It is increasingly recognized by providers that patients and their families seek to reduce the stigma of alcoholic liver disease, and a change from the term "alcoholic" to "alcohol-related" will help; thus, alcohol-related liver disease, alcohol-related steatohepatitis, and alcohol-related cirrhosis are suggested, retaining the familiar abbreviations (ALD, ASH, and AC, respectively). Due to longstanding usage, the term alcoholic hepatitis (AH) will likely persist. This article is protected by copyright. All rights reserved.

Pyrazolyl-pyrimidones inhibit the function of human solute carrier protein SLC11A2 (hDMT1) by metal chelation.

Solute carrier proteins (SLCs) control fluxes of ions and molecules across biological membranes and represent an emerging class of drug targets. SLC11A2 (hDMT1) mediates intestinal iron uptake and its inhibition might be used to treat iron overload diseases such as hereditary hemochromatosis. Here we report a micromolar (IC50 = 1.1 μM) pyrazolyl-pyrimidone inhibitor of radiolabeled iron uptake in hDMT1 overexpressing HEK293 cells acting by a non-competitive mechanism, which however does not affect the electrophysiological properties of the transporter. Isothermal titration calorimetry, competition with calcein, induced precipitation of radioactive iron and cross inhibition of the unrelated iron transporter SLC39A8 (hZIP8) indicate that inhibition is mediated by metal chelation. Mapping the chemical space of thousands of pyrazolo-pyrimidones and similar 2,2'-diazabiaryls in ChEMBL suggests that their reported activities might partly reflect metal chelation. Such metal chelating groups are not listed in pan-assay interference compounds (PAINS) but should be checked when addressing SLCs.

Scaffold Based Search on the Desferithiocin Archetype

Iron overload disorder and diseases where iron mismanagement plays a crucial role require orally available iron chelators with favourable pharmacokinetic and toxicity profile. Desferrithiocin (DFT), a tridentate and orally available iron chelator has a favourable pharmacokinetic profile but its use has been clinically restricted due to its nephrotoxic potential. The chemical architecture of the DFT has been naturally well optimized for better iron chelation and iron clearance from human biological system. Equally they are also responsible for its toxicity. Hence, subsequent research has been devoted to develop a non-nephrotoxic analogue of DFT without losing its iron clearance ability. The review has been designed to classify the compounds reported till date and to discuss the structure activity relationship with reference to modifications attempted at different positions over pyridine and thiazoline ring of DFT. Compounds are clustered under two major classes: (i) Pyridine analogues and (ii) phenyl analogue and further each class has been further subdivided based on the presence or absence and the number of hydroxy functional groups present over pyridine or phenyl ring of the DFT analogues. Finally a summary and few insights into the development of newer analogues are provided.

A hybrid (iron-fat-water) phantom for liver iron overload quantification in the presence of contaminating fat using magnetic resonance imaging.

Assessment of iron content in the liver is crucial for diagnosis/treatment of iron-overload diseases. Nonetheless, T2*-based methods become challenging when fat and iron are simultaneously present. This study proposes a phantom design concomitantly containing various concentrations of iron and fat suitable for devising accurate simultaneous T2* and fat quantification technique. A 46-vial iron-fat-water phantom with various iron concentrations covering clinically relevant T2* relaxation time values, from healthy to severely overloaded liver and wide fat percentages ranges from 0 to 100% was prepared. The phantom was constructed using insoluble iron (II, III) oxide powder containing microscale particles. T2*-weighted imaging using multi-gradient-echo (mGRE) sequence, and chemical shift imaging spin-echo (CSI-SE) Magnetic Resonance Spectroscopy (MRS) data were considered for the analysis. T2* relaxation times and fat fractions were extracted from the MR signals to explore the effects of fat and iron overload. Size distribution of iron oxide particles for Magnetite fits with a lognormal function with a mean size of about 1.17µm. Comparison of FF color maps, estimated from bi- and mono-exponential model indicated that single-T2* fitting model resulted in lower NRMSD. Therefore, T2* values from the mono-exponential signal equation were used and expressed the relationship between relaxation time value across all iron (Fe) and fat concentration as [Formula: see text], with R-squared = 0.89. The proposed phantom design with microsphere iron particles closely simulated the single-T2* behavior of fatty iron-overloaded liver in vivo.

Generation and Characterisation of KY1066, a Fully Human Antibody Targeting the Enzymatic Activity of Matriptase-2 for the Treatment of Iron Overload in Beta Thalassemia

Beta thalassemia is an inherited hemoglobinopathy caused by a genetic defect in beta-globin gene and characterised by ineffective erythropoiesis, iron overload, splenomegaly and anemia. Excessive EPO production, resulting from the anemia, has a suppressive effect on the iron regulator hepcidin leading to increased iron absorption from the gut and release from internal stores. This in turn leads to tissue iron overload in transfusion independent (NTDT) patients and exacerbates the situation in transfusion dependent (TDT) patients. Primary standard of care treatment for TDT patients involves regular blood transfusions resulting in secondary iron overload and toxic tissue damage caused by non-transferrin bound iron (NTBI), which requires iron chelator treatment. Although transfusions and iron chelation have improved TDT patient prognosis, the iron overload experienced by some patients today still represents an unmet clinical need. The role of TMPRSS6 in iron regulation is already well established and reducing Tmprss6 expression was shown to increase hepcidin expression, correcting the iron overload, splenomegaly and anemia in Hbbth3/+ mice (Guo et al, JCI, 2013). Here we describe a first-in-class antibody targeting MTP-2, termed KY1066, for the treatment of diseases of iron overload, such as beta thalassemia. Through immunising mice transgenic for human immunoglobin heavy and light chain variable regions with purified human MTP-2 extra-cellular domain (ECD) and full-length human MTP-2 expressed on cells, we were able to obtain cross-reactive, MTP-2-specific monoclonal antibodies (mAbs). Our lead molecule, KY1066, was found to be a cross-reactive neutraliser of MTP-2 enzymatic activity both in vitro and in vivo and mechanistically blocks MTP-2 through binding to the serine protease (SP) domain active site, preventing cleavage of substrates. As a result, it was seen to increase BMP/SMAD signalling and elevate levels of hepcidin expression from hepatocyte cells following a single I.P. dose (10 mg/kg) in C57BL/6J mice. The elevation of hepcidin decreased serum iron and transferrin saturation through increased internalisation and degradation of ferroportin. In Hbbth3/+ mice, a single I.P. dose (10 mg/kg) showed a decrease of 52% and 47% in serum iron and transferrin saturation (TSAT) respectively, at the 2-week timepoint. Furthermore, with repeat dosing, we were able to show consistent iron restriction in a Hbbth3/+ mice over multiple weeks. Together this provides evidence KY1066 has the potential to treat iron overloaded patients, such as in beta thalassemia, to improve the anemia and reduce the transfusion and iron chelation need. Disclosures Wake: Kymab Ltd: Employment, Equity Ownership. Papworth:Kymab Ltd: Employment, Equity Ownership. Bayliss:Kymab Ltd: Employment, Equity Ownership. Grimshaw:Kymab Ltd: Employment, Equity Ownership. Rynkiewicz:Kymab Ltd: Employment, Equity Ownership. Paterson:Kymab Ltd: Employment, Equity Ownership. Poindron:Kymab Ltd: Employment, Equity Ownership. Carter:Kymab Ltd: Employment. Hudson:Kymab Ltd: Employment, Equity Ownership. Theurl:Kymab Ltd: Consultancy, Equity Ownership. Germaschewski:Kymab Ltd.: Employment, Equity Ownership. Meynard:Kymab Ltd: Research Funding.

Role of Dietary Flavonoids in Iron Homeostasis.

Balancing systemic iron levels within narrow limits is critical for human health, as both iron deficiency and overload lead to serious disorders. There are no known physiologically controlled pathways to eliminate iron from the body and therefore iron homeostasis is maintained by modifying dietary iron absorption. Several dietary factors, such as flavonoids, are known to greatly affect iron absorption. Recent evidence suggests that flavonoids can affect iron status by regulating expression and activity of proteins involved the systemic regulation of iron metabolism and iron absorption. We provide an overview of the links between different dietary flavonoids and iron homeostasis together with the mechanism of flavonoids effect on iron metabolism. In addition, we also discuss the clinical relevance of state-of-the-art knowledge regarding therapeutic potential that flavonoids may have for conditions that are low in iron such as anaemia or iron overload diseases.

Abstract 1889: Chronic exposure to excess iron promotes EMT and cancer via p53 loss in pancreatic cancer

Abstract Pancreatic cancer especially the pancreatic ductal adenocarcinoma (PDAC) is by far the most lethal of all cancers with a five year survival rate of less than 5%. Gemcitabine is currently used as a first line therapy for locally advanced and metastatic PDAC but with a very low success rate. Hence, there is an urgent need to better understand what actually drives this cancer so as to come up with a better diagnostic and therapeutic strategies. Excess heme and iron are known to be pro-tumorigenic. When present in excess, these molecules become toxic. Fe2+ in free form is a potent oxidant; it catalyzes the Fenton reaction to generate hydroxyl radicals (Fe2++ H2O2 → Fe3+ + HO• + OH-), a potent reactive oxygen species. Free heme is also toxic as it catalyzes free radical reaction and induces oxidative damage. Accumulation of iron and heme to toxic levels occurs in genetic diseases (hemochromatosis, sickle cell disease), pathological conditions (hemolytic anemia, ischemia reperfusion), infections, and clinical/therapeutic conditions (repeated blood transfusion). Excess intake of iron and heme from dietary sources could also lead to iron/heme overload, particularly in the colon. In this regard, red meat with its ~10-fold higher heme content than white meat is specifically relevant. Among these conditions however, hemochromatosis deserves special mention. Based on the evidence that hemochromatosis, an iron-overload disease, drives hepatocellular carcinoma, we hypothesized that chronic exposure to excess iron, either due to genetic or epigenetic causes, predisposes an individual to cancer. We employed cell culture studies to interrogate the connection between excess iron and cancer in multiple tissues and combined in vitro and in vivo studies to explore the connection in pancreas further. Ferric ammonium citrate was used as an exogenous iron source. Chronic exposure to excess iron induced epithelial-mesenchymal transition (EMT) in normal and cancer cell lines, loss of p53, and suppression of p53 transcriptional activity. In order to further extrapolate our cell culture data, we generated EL-KRASG12D or EL-Kras mouse (pancreatic neoplastic mouse model) expressing Hfe+/+ and Hfe-/- genetic background. p53 target gene expression decreased in EL-Kras/Hfe-/- mouse pancreas compared to EL-Kras/Hfe+/+ mouse pancreas. Interestingly, the incidence of acinar-to-ductal metaplasia and cystic pancreatic neoplasms (CPN) decreased in EL-Kras/Hfe-/- mice, but the CPNs that did develop were larger in these mice than in EL-Kras/Hfe+/+ mice. In conclusion, these in vitro and in vivo studies support a potential role for chronic exposure to excess iron as a promoter of more aggressive disease via p53 loss within pancreatic epithelial cells. Citation Format: Devaraja Rajasekaran, Jiro Ogura, Mitchell Wachtel, Sabarish Ramachandran, Ellappan Babu, Sathish Sivaprakasam, Paul J. Grippo, Carolina Torres, Thangaraju Muthusamy, Jaya P. Gnana-Prakasam, Yangzom D. Bhutia. Chronic exposure to excess iron promotes EMT and cancer via p53 loss in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1889.

Abstract 1479: Bacterial dysbiosis in the mouse model of hemochromatosis: Increased risk of colitis and colitis-associated colon cancer

Abstract Hemochromatosis, an inherited iron-overload disease, causes tissue damage due to deposition of iron in toxic levels in most tissues including the liver, heart, kidney, pancreas and colon. Free iron, both in the inorganic form (i.e, non-transferrin-bound and non-ferritin-bound) and organic form (i.e. heme), facilitates Fenton reaction to generate hydroxyl radicals and to induce cellular oxidative damage that is observed in carcinogenesis. The primary site of iron deposition in hemochromatosis patients is liver, and therefore, liver cancer formation in these patients has been studied extensively. However, little is known about the iron-elicited colonic pathologies, mainly colonic inflammation and colon cancer. Here we postulate that iron overload as observed in hemochromatosis disrupts healthy colonic homeostasis and exacerbates the development of colon inflammation and colon cancer. To test our hypothesis, we examined the progression and severity of colitis and colon cancer in Hfe-/- mouse and the wild type control. Hfe-/- mouse is a model for classical hemochromatosis. Besides serum and liver, high concentrations of iron and heme deposits are found in the colon of Hfe-/- mouse. Experimental colitis was induced by administration of Dextran Sodium Sulfate (DSS) in drinking water. Colitis-associated colon cancer was initiated by the intraperitoneal injection of carcinogen, azoxymethane (AOM) and the carcinogenesis was driven by DSS administration. Colonic inflammation was more severe in the Hfe-/- mouse than in control. In addition, hemochromatosis mouse developed more and larger colonic polyps than the control group. We observed that this high susceptibility to colitis and colon cancer in Hfe-/- but not wild type mouse, lies in the differences in strains regarding the bacterial composition and colonic defense machinery. 16S ribosomal RNA sequencing of fecal bacteria revealed that the microbiota composition of Hfe-/- mouse altered to favor the pathogenic bacteria that belong to phyla Proteobacteria and TM7. In addition, the Hfe-/- proinflammatory bacteria adhered to colon and thus increased the colonic bacterial load. This phenomenon, addressed as bacterial dysbiosis, is considered a hallmark of colon inflammation and colon cancer. Furthermore, we observed that the colonic epithelial cells of Hfe-/- mouse had a lower expression of antimicrobial peptides and thus a defective first line defense against the pathogens. Finally, hemochromatosis mouse colon under inflammation released higher concentration of the pro-inflammatory cytokines that contributed to the creation of the hostile colonic environment. In summary, iron overload as seen in hemochromatosis, impairs the colonic defense machinery and it causes bacterial dysbiosis, thus providing the ideal environment for the colitis and colon cancer development. Citation Format: Bojana Ristic, Sathish Sivaprakasam, Rao Kottapalli, Abdul Hamood, Vadivel Ganapathy. Bacterial dysbiosis in the mouse model of hemochromatosis: Increased risk of colitis and colitis-associated colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1479.

PB2412 ADULT THALASSEMIA PATIENTS OF PEDIATRIC HEMATOLOGY CLINIC: A SINGLE CENTER EXPERENCE IN TURKEY

Background:Advances in understanding and treatments in transfusion dependent thalassemia (TDT) improved the clinical outcomes. Disease‐related complications seem to be the challenging problem in aging patients with thalassemia who now survive longer than in the past.Aims:Here we aimed to describe clinical features of adult thalassemia patients followed on the pediatric hematology clinic.Methods:All the patients with TDT and older than 25‐years were reviewed retrospectively. Demogrophical, cilinical features, status of iron overload and treatment and disease related complications were recorded.Results:A total of 69 patients were evaluated. Thirty three were female and 36 were male. Mean age was 32.9 years (range 25‐53 years). Mean duration of follow‐up and iron chelation therapy were 31,2 years (range 14‐50 years), and 25 years (range 7‐ 31 years), respectively.Fortyfour patients had splenectomy. Mean ferritin levels was found to be 1645 ng/ml (range between 361‐8600 ng/ml). Cardiac iron status were evaluated in 44 patients and cardiac T2∗was normal (>20 msec) in 40 patients, moderate and severe iron overload was shown in 1 and 3 patients, respectively. 1 patients had moderate. Liver iron status was normal (<2 mg) in 16 out of 53 patients with liver T2∗ MRI. Liver iron overload was found to be mild (2‐5 mg) in 11 patients, moderate (5‐10 mg) in 10 patients and severe (>10 mg) in 16 patients. A strong positive correleation was found between serum ferritin levels and liver iron overload (p < 0.001). There was no significant association between cardiac iron overload and serum ferritin levels. Also a slight association was shown cardiac and liver iron overload (p = 0.03).Summary/Conclusion:In our country the adult TDT patients are still on follow‐up in pediatric hematology clinics based on the experience of the pediatric hematologists on those patients. Although these older patients were constituted a new cohort, in this study the clinical features and status of iron overload in older TDT patients were found to be acceptable and similar to younger TDT's regarding despite long period of regular transfusion and histroical features of the treatment.

PB2373 LIVER DISEASE DURING AND AFTER AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION IN EGYPT (SINGLE CENTER EXPERIENCE)

Please indicate where the abstract has been published before: egyptian socitey of hepatology and gastroenterology journalBackground:Hematopoietic stem cell transplantation has a rapid increase over the last decade. It is an established therapy for many hematological disorders. HSCT had many possible serious complications. One of those complications is hepatic dysfunction.Hepatic complication in autologous HSCT survivors could be early complications include drug toxicity, infections and long‐term liver complications from chronic viral hepatitis, iron overload or original disease relapse.Aims:is to determine the prevalence, etiology of liver disease in Egyptian population who had HSCTMethods:this study is cross‐sectional study in December 2016 including 88 patients who had autologus transplantation in Ain Shams University HospitalsResults:In autologus patients the first cause of hepatotoxicity is conditioning regimen involving 27% of the patients. Second cause is flare of viral hepatitis affecting 8% of the patients. In third place is sepsis that leads to elevated liver function which occurred in 6% of our patients, these figures were also dramatically changed after D + 100 and lower hepatotoxicity percentage occurs as 11% of the patients had liver injury caused by drugs and only 1% patients had viral hepatitis reactivation.imageSummary/Conclusion:Drug hepatotoxicity is main cause of liver injury in BMT unit in Ain Shams University in Egyptian population.

Deferoxamine-inducedhigh expression of TfR1 and DMT1 enhanced iron uptake intriple-negative breast cancer cells by activatingIL-6/PI3K/AKTpathway.

Background: Deferoxamine (DFO) is a commonly used iron chelator, which can reduce the iron levels in cells. DFO is normally used to treat iron-overload disease, including some types of cancer. However, our previous studies revealed that DFO treatment significantly increased the iron concentrations in triple-negative breast cancer cells (TNBCs) resulting in enhanced cell migration. But the mechanism of DFO-induced increasing iron uptake in aggressive TNBCs still remained unclear.Materials and methods: Iron metabolism-related proteins in aggressive breast cancer MDA-MB-231, HS578T and BT549 cells and nonaggressive breast cancer MCF-7 and T47D cells were examined by immunofluorescence and Western blotting. The possible regulatory mechanism was explored by Western blotting, co-incubation with neutralizing antibodies or inhibitors, and transwell assay.Results: In this study, we found that DFO treatment significantly increased the levels of iron uptake proteins, DMT1 and TfR1, in aggressive TNBCs. Moreover, both TfR1 and DMT1 expressed on cell membrane were involved in high iron uptake in TNBCs under DFO-induced iron deficient condition. For the possible regulatory mechanism, we found that DFO treatment could promote a high expression level of IL-6 in aggressive MDA-MB-231 cells. The activated IL-6/PI3K/AKT pathway upregulated the expression of iron-uptake related proteins, TfR1 and DMT1, leading to increased iron uptakes.Conclusion: We demonstrated that DFO could upregulate expression of TfR1 and DMT1 , which enhanced iron uptake via activating IL-6/PI3K/AKT signaling pathway in aggressive TNBCs.

Recent progress on inhibitors of the type II transmembrane serine proteases, hepsin, matriptase and matriptase-2.

Members of the type II transmembrane serine proteases (TTSP) family play a vital role in cell growth and development but many are also implicated in disease. Two of the well-studied TTSPs, matriptase and hepsin proteolytically process multiple protein substrates such as the inactive single-chain zymogens pro-HGF and pro-macrophage stimulating protein into the active heterodimeric forms, HGF and macrophage stimulating protein. These two proteases also have many other substrates which are associated with cancer and tumor progression. Another related TTSP, matriptase-2 is expressed in the liver and functions by regulating iron homoeostasis through the cleavage of hemojuvelin and thus is implicated in iron overload diseases. In the present review, we will discuss inhibitor design strategy and Structure activity relationships of TTSP inhibitors, which have been reported in the literature.

Decrease of Peripheral Monocyte Relative Number and Mean Platelet Volume in Iron Overloaded Mice

Iron overload (IO) because of multiple blood transfusion as a definite therapy for hematological disease with chronic and severe anemia has become a major concern. Deleterious complication contributed by chemically reactive deregulated iron may affect cellular homeostasis systemically lead to tissue and organ damage. When this toxicity occurred in blood cells, alteration of peripheral hematological profile concerning erythrocyte, leucocyte, and platelet most likely to be modified and imperatively need to be evidenced. The experimental IO mice model was established by injecting a low and high dose of iron dextran intraperitoneally. Peripheral erythrocyte, leucocyte and platelet indices measured by hematology analyzer were analyzed. A dynamic tendency of leucocyte absolute cell number and differential cell count of low and high dose iron treatment and a significant decrease of differential monocyte count were found. In addition, high dose iron treatment showed a significantly lower mean platelet volume. In conclusion, this study verified that IO impaired the cellular hematological indices by selectively suppress monocyte number addressing that this mononuclear phagocyte was the most affected immune cell. Furthermore, low mean platelet volume following acquired platelet function defect was evidenced. This research provided an animal experimental model that could be used for further study in finding alternative therapeutic targets on the pathophysiology of iron overload diseases, such as thalassemia.