Iron metabolism is the process of absorption, transport, storage and conversion and excretion of the essential trace element iron in living organisms. Normal iron metabolism tightly regulates iron content at the systemic and cellular levels through a variety of related proteins to prevent excessive free radicals from being generated during the iron cycle that can damage the body. Various abnormalities in iron metabolism are found in a variety of lymphohaematopoietic tumours and an insidious link between iron metabolism and tumour development has been revealed. Serum ferritin levels and abnormalities of iron transport proteins, transferrin and their receptors can be used as prognostic indicators for lymphohematopoietic tumours and have opened up new directions of diagnosis and treatment, with a large number of novel drugs targeting tumours emerging to date. This article briefly describes the normal iron metabolism process and highlights the progress of research on abnormal iron metabolism in lymphohematopoietic tumors at the systemic and cellular levels.
Hematopoiesis ; Humans ; Iron/metabolism* ; Neoplasms ; Receptors, Transferrin/metabolism* ; Transferrin/metabolism*

Iron is one of the necessary elements for cell growth, proliferation and functional activities. Iron uptake of the vast majority cells, including tumor cells, is primarily mediated by transferrin receptor (TfR). Studies showed that transferrin receptor expressed on tumor cell surface at a high level, thus can be used in the treatment for malignant tumor combined with many kinds of materials. In this article, recent progress of study on transferrin receptor used in treating hematological malignant tumor are reviewed from aspects of transferrin receptor combined with drugs including artemisinin, doxorubicin, gambogic acid and so on, genes, antibodies, polyethylene glycol and nanoparticles.
Hematologic Neoplasms ; metabolism ; therapy ; Humans ; Receptors, Transferrin ; metabolism ; therapeutic use

Animals ; Blood-Brain Barrier ; metabolism ; Ferritins ; metabolism ; Horses ; Mice ; Receptors, Transferrin ; metabolism ; Spleen ; chemistry

This study was purposed to investigate the iron metabolism changes and their clinical significance in myelodysplastic syndrome (MDS). Thirty eight transfusion independent MDS patients and 49 controls (21 AA patients, 28 normal volunteers) were enrolled in this study. The iron metabolism indicators including serum iron protein (SF), serum iron (SI), transferrin protein (Tf), total iron binding capacity (TIBC), transferrin saturation (TS), soluble transferrin receptor (sTfR) were detected, the intracellular and extracellular iron distribution were observed under microscope, the chromosome karyotype was analysis by FISH. The results showed that the serum SF, SI and TS levels in MDS group were lower than those in AA group, the serum SF value was higher than that in normal control group. There was no statistical difference between the SI, TS levels as compared with normal control group. The SI, TS levels showed a positive correlation with SF level(r = 0.281, P = 0.007; r = 0.338, P = 0.001, respectively). The serum TIBC in MDS group was no statistically significant difference from that in the control group. The Tf level in MDS group was higher than that in AA and normal control groups, and Tf level between later 2 groups did not show statistical difference. The proportion of sideroblasts in MDS group (57.19 ± 19.11%)was higher than that in AA group (35.00 ± 20.67%). The extracellular iron (+ + +- + + + +) (24%)was lower than that in AA group (33%), and bone marrow particle dyeable iron displayed mainly cocci-like distribution under microscope in patients with increased extracellular iron (+ + +- + + + +), while small need or massive distribution was observed in AA group.In addition, the abnormal chromosome karyotype was found in 15 out of 19 MDS cases (79%). There was no difference in iron metabolism indicators between the high-risk group and the low-risk group of MDS divided according to the International Prognostic Scoring System (WPSS). It is concluded that the iron loading in transfusion-independent patients obviously increases, displaying the enhancement of SF, Tf, intra-and extra-cellular iron, but lower than those in AA patients. It suggests that the abnormality exists in process of use, storage and discharge of iron in MDS patients.
Adult ; Case-Control Studies ; Female ; Ferritins ; blood ; Hematopoiesis ; Humans ; Iron ; blood ; metabolism ; Male ; Middle Aged ; Myelodysplastic Syndromes ; blood ; metabolism ; physiopathology ; Receptors, Transferrin ; metabolism ; Transferrin ; metabolism

OBJECTIVEFunctionally, erythropoietin (EPO) can promote the proliferation and growth of erythroid progenitor cells, and it is widely used in the treatment of anemia in chronic diseases caused by tumor and inflammation. However, it is unclear whether EPO has any effect on tumor cell iron metabolism and tumor cell proliferation. The purpose of this study was to explore the effects of recombinant human EPO (rhEPO) on the expression of transferrin receptor (TfR, CD(71) antigen) of leukemic cell K562 and its relation to cell cycle.

METHODSIn vitro culture of K562 cell was performed with additions of various concentrations of rhEPO and Fe. Treatments were terminated at 24 h and 72 h, respectively. Then each group of cells was incubated with FITC-IgG antibody to CD(71) or PI, a kind of DNA dye. And TfR expression and DNA synthesis status were analyzed by flow-cytometry.

RESULTS(1) The expression of TfR by K562 cells increased significantly when incubated for 72 h with different concentrations of rhEPO. The measurement values of 5 U/ml, 10 U/ml and 20 U/ml groups were 12.2 +/- 1.40, 10.7 +/- 0.99 and 11.1 +/- 0.90, respectively. They were markedly increased when compared with that of control group (6.27 +/- 0.11, P < 0.05). (2) When incubated with rhEPO (5 u/ml) alone or combined with FeCl(3) (100 micro mol/L), the percentages of cells in S phase were 51.1% and 59.6%, respectively. They significantly increased when compared with that of control group (42.9%, P < 0.05).

CONCLUSIONSIron is very important for the proliferation of both normal cells and leukemic cells. It is essential to the activity of ribonucleotide reductase (RR). The authors hypothesized that rhEPO would increase the expression of TfR and intracellular iron content of leukemic cells, which would enhance the DNA synthesis and cell proliferation. Therefore, the clinical application of rhEPO to promote erythropoiesis of cancer patients should be cautious.

Cell Cycle ; drug effects ; Erythropoietin ; pharmacology ; Flow Cytometry ; Humans ; K562 Cells ; Receptors, Transferrin ; metabolism ; Recombinant Proteins

Iron homeostasis plays an important role for the maintenance of human health. It is known that iron metabolism is tightly regulated by several key genes, including divalent metal transport-1(), transferrin receptor 1(), transferrin receptor 2(), ferroportin(), hepcidin(), hemojuvelin() and . Recently, it is reported that DNA methylation, histone acetylation, and microRNA (miRNA) epigenetically regulated iron homeostasis. Among these epigenetic regulators, DNA hypermethylation of the promoter region of , and bone morphogenetic protein 6 () genes result in inhibitory effect on the expression of these iron-related gene. In addition, histone deacetylase (HADC) suppresses gene expression. On the contrary, HADC inhibitor upregulates gene expression. Additional reports showed that miRNA can also modulate iron absorption, transport, storage and utilization via downregulation of and other genes. It is noteworthy that some key epigenetic regulatory enzymes, such as DNA demethylase TET2 and histone lysine demethylase JmjC KDMs, require iron for the enzymatic activities. In this review, we summarize the recent progress of DNA methylation, histone acetylation and miRNA in regulating iron metabolism and also discuss the future research directions.
Epigenesis, Genetic ; Gene Expression Regulation ; genetics ; Homeostasis ; Humans ; Iron ; metabolism ; Receptors, Transferrin

OBJECTIVETo investigate the systemic changes of iron metabolism following manganese exposure.

METHODSNinety-seven welders and 91 workers with no history of exposure to manganese were recruited from the same factory in Beijing serving as the exposure group and the control group respectively. The welding rods used were type J422. The concentration of the manganese in the air of the work place was determined respectively with the national standard method. The serum iron and manganese, ferritin, transferrin and transferrin receptors were measured with the graphite furnace atomic absorption spectrophotometry and ELISA in both groups.

RESULTSThe permissible concentration-STEL of ambient Mn in welders' breathing zone ranged from 0.53 mg/m(3) to 2.19 mg/m(3), while the permissible concentration-TWA of ambient Mn was between 0.29 mg/m(3) and 0.92 mg/m(3) in the breathing zone of the workplace. Serum Mn and Fe concentrations in welders were about 1.40 times (P < 0.0l) and 1.2 times (P < 0.01), respectively, higher than those of control subjects. At the same time, the transferrin concentrations in serum were significantly higher (about 1.2 times, P < 0.05) in welders than in controls. In contrast, transferrin receptors were significantly lower (about 1.2 times) in exposed subjects than controls (P = 0.001). There was no difference in serum ferritin between the two groups (P = 0.112). Although there was no significant trend, the serum ferritin level was increased by 18% in comparison with that of the control. The abnormal percentage of serum Fe and Serum Mn in welders were 55.67% and 67.01% respectively, higher than those of control subjects. In addition, the correlations between all indicators and the duration of employment were not observed.

CONCLUSIONThe long term exposure to the manganese can induce the disorder of the iron metabolism, which is found in the expression of increase of the serum iron and transferrin as well as the decrease of transferrin receptors.

Female ; Ferritins ; blood ; Humans ; Iron ; metabolism ; Iron Metabolism Disorders ; chemically induced ; Male ; Manganese ; adverse effects ; Occupational Exposure ; adverse effects ; Receptors, Transferrin ; blood ; Transferrin ; analysis ; Welding

Myelodysplastic syndrome (MDS) is a heterogeneous disease characterized by dysplasia and ineffective hematopoiesis. The dysplasia is crucial in the diagnosis of MDS, but the morphologic abnormalities of bone marrow cells are not specific for MDS. When the morphological evaluation of marrow dysplasia and cytogenetics can not give enough informations, for diagnosis of MDS, the application of flow cytometry (FCM) for immunophenotyping in MDS will become particularly important. Multiparametric evaluation of myeloid, monocytic maturation and antigen expression pattern contribute to the identification of two or more aberrancies in MDS cases. FCM evaluation of erythroid dysplasia is particularly difficult, because of the limited availability of specific markers. By analyzing the proteins involved in cellular iron metabolism, MDS erythroid cells present an "iron-loaded" phenotype characterized by increased ferritin contents and reduced transferrin receptor, which reflects the degree of dysplasia assessed by morphology. The proportion of CD34(+) cells increased, abnormal expression of surface antigen is also important. The application of flow cytometry in detecting dysplasia of myelodysplastic syndrome is discussed in this article.
Bone Marrow Cells ; pathology ; Erythroid Cells ; metabolism ; Flow Cytometry ; Humans ; Myelodysplastic Syndromes ; blood ; diagnosis ; pathology ; Receptors, Transferrin ; metabolism

The aim of this study was to investigate the expression of transferrin receptor 2 (TfR2) mRNA in bone marrow mononuclear cells (BMMNC) of children with hyperplastic anemia (HA), to analyze the correlation of TfR2 mRNA expression level with Hb level, bone marrow erythroid hyperplasia, iron status in body and underlying diseases, and to evaluate the role of TfR2 in erythroid hemopoiesis and the useful value in diagnosis of HA. The experiment was divided into 2 groups: test group, in which 40 patients with HA were enrolled, and control group in which 10 patients without erythroid disorders and hematological malignancies confirmed by bone marrow examination were enrolled. The bone marrow samples of patients in mentioned above 2 groups were collected, the TfR2 mRNA expression in BMMNC of patients with HA was detected by fluorescence-quantitative PCR, the correlation of HA with bone marrow erythroid hyperplasia, iron status of body and underlying diseases was analyzed. The results showed that the relative level of TfR2 mRNA expression in HA patients was significantly higher than that in control patients. The TfR2 mRNA expression level negatively correlated with Hb level in peripheral blood (r = -0.715), while it positively correlated with ratio of bone marrow erythroblasts (r = 0.533). It is concluded that TfR2 mRNA expression in HA patients increases and closely correlates with hyperplasia status of bone marrow and anemia level in peripheral blood.
Adolescent ; Anemia ; metabolism ; pathology ; Bone Marrow Cells ; metabolism ; Case-Control Studies ; Child ; Child, Preschool ; Erythroid Precursor Cells ; metabolism ; Female ; Humans ; Infant ; Male ; RNA, Messenger ; metabolism ; Receptors, Transferrin ; metabolism

OBJECTIVETo investigate the mRNA expression of transferrin receptor 1 (TfR1) and iron regulatory protein 1 (IRP1) in the full-term placenta from different maternal iron status, and explore the mechanism of placental iron transport and regulation.

METHODSThe mRNA level of TfR1 and IRP1 in full-term placentae was detected by reverse transcription polymerase chain reaction (RT-PCR) in normal group (N), iron deficiency group (ID) and iron deficiency anemia group (IDA).

RESULTS(1) The expression of TfR1 mRNA in N group was 0.4813 +/- 0.1891, in ID group was 0. 6647 +/- 0.2788, and in IDA group was 0.9767 +/- 0.2858. There was significant difference between IDA group and N group or ID group (t = 0.002, P < 0.01 or t = 0.028, P < 0.05), and was no difference between ID group and N group (t = 0.117, P > 0.05). (2) The expression of IRP1 mRNA in N group was 0.2616 +/- 0.0785, in ID group was 0.3696 +/- 0.1801, and in IDA group was 0.3971 +/- 0.0902 and was no difference among the three groups (F = 1.845, P = 0.179).

CONCLUSIONSThe expression of TfR1 mRNA is increased when maternal iron deficiency progressed while there is no change in the expression of IRP1 mRNA in the placentae of TfR1 mRNA indicated that IRP1 takes part in the regulation of placenta iron transport.

Anemia, Iron-Deficiency ; genetics ; Antigens, CD ; metabolism ; Female ; Humans ; Iron Regulatory Protein 1 ; metabolism ; Placenta ; metabolism ; Pregnancy ; RNA, Messenger ; metabolism ; Receptors, Transferrin ; metabolism