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

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

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

The binding mechanism between pefloxacin mesylate (PM) and transferrin (Tf) was explored using spectral experiment combined with molecular modeling techniques. The binding parameters and thermodynamic functions of PM-Tf solution system were measured at different temperatures. The effect of PM on molecular conformation of Tf was investigated and the interaction mechanism was also discussed. The results showed that dynamic quenching mechanism occurs with PM binding to Tf. The value of binding distances (r) is low, which indicates the occurrence of energy transfer. The drug had conformational effect on Tf, which resulted in changes of hydrophobic environment of the binding domain in Tf. According to the obtained thermodynamic parameters, the main interaction force between PM and Tf is attributed to hydrophobic bonding. The results of molecular modeling revealed that hydrophobic and hydrogen bonds are main binding forces in the PM-Tf system. These results were in accordance with spectral experiments. The research results have given a better theoretical reference for the study of pharmacological mechanism between protein and quinolone.
Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; Pefloxacin ; chemistry ; metabolism ; Protein Binding ; Protein Conformation ; Thermodynamics ; Transferrin ; chemistry ; metabolism

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

Anemia, Hypochromic ; etiology ; Humans ; Iron ; metabolism ; Protein Deficiency ; complications ; congenital ; Transferrin ; deficiency

BACKGROUND: Hepcidin, a key regulator of iron homeostasis, is associated with iron metabolism imbalance in patients with chronic kidney disease (CKD). However, serum hepcidin level in anemic patients with CKD presents a contradictory picture. We investigated the relationship between serum hepcidin-25 level and iron parameters in patients with CKD. METHODS: We defined and categorized patients with CKD according to the Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines. We analyzed the relationship between serum hepcidin-25 level and iron parameters [serum iron, total iron-binding capacity (TIBC), unbound iron-binding capacity (UIBC), transferrin saturation, and ferritin levels] according to the CKD stage and clinical and laboratory characteristics. RESULTS: Hb level, TIBC, and UIBC decreased and ferritin level increased (Ptrend<0.001) (stage 1-2, 28; stage 3, 40; stage 4, 36; stage 5, 42) as the CKD stage progressed. Serum hepcidin-25 level showed no significant trend with the progressing CKD stage [stage 1-2, 13.7 (3.7-25.0) ng/mL; stage 3, 14.0 (0.8-26.5) ng/mL; stage 4, 13.9 (2.0-32.1) ng/mL; stage 5, 13.8 (0.5-42.4) ng/mL; Ptrend=0.618]. No significant relationship was noted between serum hepcidin-25 level and kidney function parameters, Hb levels, or iron parameters (P>0.05). CONCLUSIONS: Serum hepcidin-25 level was not found to be associated with iron parameters or clinical status of CKD patients in our study. Determination of hepcidin-25 levels may not provide more information than conventional iron parameters in monitoring iron metabolism in CKD patients. However, further studies are needed to establish the clinical utility of hepcidin measurement in CKD patients.
Anemia ; Ferritins ; Hepcidins* ; Homeostasis ; Humans ; Iron* ; Kidney ; Kidney Diseases ; Metabolism ; Renal Insufficiency, Chronic* ; Transferrin

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