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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Placental isoferritin (PLF) and its unique superheavy chain p43 have been recently described as being synthesized by breast cancer cell lines but not by normal breast epithelial cells. Since previous reports have demonstrated a correlation between the content of 'normal' ferritin in breast cancer tissue and the degree of differentiation and prognosis, we have determined p43 in the cytosol of 122 breast cancer samples by use of the new monoclonal antibody CM-H-9. The synthesis of p43 showed a significantly negative correlation with tumor size (P = 0.0001), histologic grading (P = 0.0038), nuclear pleomorphism (P = 0.0019), rate of mitosis (P = 0.0002), lymphocytic reaction (P = 0.0001) and a significantly direct correlation with estrogen receptor status (P = 0.0009). Although patients with a higher p43 content showed a trend for a better outcome (median follow-up: 61.4 months), an independent influence of the cytosolic p43 content on survival could not be confirmed by a multiple Cox model. Therefore it seems that p43's prognostic impact is linked to the highly significant correlation with features of differentiation although a statistical bias in the Cox model due to the limited number of patients must also be taken into account. On the other hand, the significant correlation of p43 expression with factors for good prognosis was striking and consistent and warrants further research of this tumor product.
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PMID:Expression of p43 in breast cancer tissue, correlation with prognostic parameters. 142 43

Placental isoferritin (PLF), an acidic isoform of ferritin, and its unique superheavy chain p43 have been recently described to be synthesized by breast cancer cell lines but not by normal breast epithelial cells. Since previous reports have demonstrated a correlation between the content of 'normal' ferritin in breast cancer tissue, degree of differentiation, and prognosis, we have tried to evaluate the correlation of p43 in the cytosol of 122 breast cancer samples with commonly applied prognostic factors and features of proliferation and differentiation. In parallel, we investigated the correlation of p43 expression in MCF-7 and T47-D breast cancer cell lines during proliferation induced by estradiol plus fetal calf serum (assessed by 3H-thymidine incorporation), compared to p43 expression in stationary non-stimulated cell cultures. The levels of p43 in breast cancer cytosols correlated significantly negatively with tumor size (p = 0.0001), histologic grading (p = 0.0038), nuclear pleomorphism (p = 0.0019), rate of mitosis (p = 0.0002), and lymphocytic reaction (p = 0.0001), and significantly directly with the estrogen receptor status (p = 0.0009). Although patients with a higher p43 content showed a trend for a better outcome (median follow-up: 61.4 months), an independent influence of the cytosolic p43 content on survival could not be confirmed by a multivariate Cox model. In accordance with the observed negative correlation of features of differentiation vs. p43 expression, induction of proliferation by estradiol plus FCS added to serum-free tissue culture medium correlated with a decrease of p43 synthesis in both cell lines. Expression of p43 in estrogen and FCS-absent media revealed also a decrease in relation to a low spontaneous proliferation. However, the drop of p43 synthesis was significantly stronger in cell lines with estrogen-stimulated proliferation. Our in vitro and cytosol results confirm recent clinical observations describing an inverse correlation of p43 synthesis with the degree of proliferation and differentiation in breast cancer. However, the pathologic mechanisms leading to this phenomenon as well as the negative correlation with lymphocytic infiltration are still unclear and need to be further elucidated.
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PMID:Placental isoferritin associated p43 antigen correlates with features of high differentiation in breast cancer. 146 68

Placental isoferritin (PLF), an acidic isoform of ferritin, and its unique superheavy chain of 43 kDa (p43) has been described to be synthesized by human breast cancer cells. Physiologically, p43 PLF produced by the placenta is involved in immune suppression of maternal lymphocytes aimed at fetal antigens. A study was carried out to elucidate a paradigm of p43 occurrence in breast cancer patients. Immunosuppression of cytotoxic CD8+ lymphocytes was measured via inhibition of blast transformation in concanavalin A (ConA) stimulated peripheral blood lymphocytes (PBL) using 3H-thymidine uptake in vitro. PBLs were cultivated from 29 women having benign lesions in the breast as well as from 41 patients with breast adenocarcinoma. In breast cancer patients addition of p43 significantly inhibited the activation of lymphocytes proliferation by ConA compared to women with benign tumors. The addition of indomethacin or levamisole did not influence this inhibitory effect of p43 in breast cancer patients. Presence of interleukin-2 in cultures was able to overcome the inhibitory effect of p43 on CD8+ lymphocytes proliferation from women having breast adenocarcinomas and to increase its value in patients with benign lesions.
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PMID:Immunosuppressive activity of lymphocyte mitogenesis by breast cancer-associated p43. 899 59

Human placental isoferritin (PLF) is a sub-type of human ferritin mainly composed of a 43 kD protein, which has an immunosuppressive activity and may be involved in the downregulation of the maternal immune system during pregnancy. The aim of this study was to evaluate the distribution of p43 in the placental tissue of abnormal first trimester pregnancies. Samples of villous and decidual tissues were collected between 7 and 12 weeks' gestation from 28 missed abortions and eight complete moles. Samples of placental tissue from 20 normal pregnancies of similar gestational age were used as controls. The localization of p43 was determined by immunohistochemical techniques using CM-H9 monoclonal antibody. Compared to controls, specific p43 immunoreactivity was low in the villous syncytiotrophoblast of missed abortions and absent from all villous cellular types in complete moles. These findings correlate well with the low level of maternal serum PLF found previously in early pregnancy failures and molar gestation. This suggests that PLF may be involved in the pathogenesis of early pregnancy disorders related to an abnormal placentation.
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PMID:Diminished expression of placental isoferritin p43 component in first trimester abnormal pregnancies. 1083 77

Human placental isoferritin is composed of a 43 kDa subunit and ferritin light chains. It acts as an immunosuppressive cytokine in normal gestation and in some malignant conditions. We investigated p43-placental isoferritin expression at the maternal fetal tissue interface and in fetal kidneys in Down's syndrome (DS) compared with normal control samples. Following termination of mid-gestation pregnancies placental and fetal kidney tissue samples were collected. Immunohistochemical analysis of the specimens was performed using a monoclonal antibody generated against human p43-placental isoferritin protein (CM-H-9 mAb). Expression of p43-placental isoferritin was detected in Hofbauer cells and in the syncytial layer of placental tissue. Significantly higher numbers of positive Hofbauer cells were detected in DS placentae at 17 weeks gestation compared with the controls. The number of immunopositive Hofbauer cells decreased in DS placentae at 20 weeks gestation, 3 weeks later than in controls. In kidneys of fetuses at 17 weeks gestation, p43-placental isoferritin immunoreactivity was confined to the proximal tubules of the nephrons. DS kidneys had higher staining intensities compared with similar gestational age controls. Enhanced expression of p43-placental isoferritin was observed in DS placentae and fetal kidneys. This may explain the increased p43-placental isoferritin levels in the maternal serum of DS gestations.
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PMID:Enhanced expression of the immunoregulator, p43-placental isoferritin, in Down's syndrome placentae and fetal kidneys. 1246 46

Previously we have demonstrated an apoptosis inducing activity for a rat hepatocyte conditioned medium (CM) presumably mediated by acidic isoferritins. Here, we present support for this assumption since isoferritins purified from different rat hepatocyte CM significantly enhanced the frequency of apoptotic cells in primary rat hepatocytes, an effect completely inhibited by a neutralizing anti-H-ferritin antibody. The apoptosis induction appears to be related to a 43 kDa ferritin subunit contained in the isoferritins released from primary hepatocytes, presumably representing a ferritin heavy/light chain heterodimer. In addition, these isoferritins immunologically crossreact with antibodies raised against placental isoferritin p43-PLF (which also contains a 43 kDa ferritin subunit) and melanoma-derived H-chain ferritin, representing ferritin isoforms which reveal immunomodulatory properties. Furthermore, p53 and FasL are upregulated upon isoferritin treatment in a time dependent mode, and apoptosis induction can be suppressed by neutralizing anti-FasL antibodies. Proapoptotic Bid is upregulated too and translocated into mitochondria in primary hepatocytes exposed to the isoferritins purified from the CM. Finally, epidermal growth factor (EGF) and dexamethasone (DEX), which counteract proapoptotic mitochondrial signalling, almost completely abolished the proapoptotic effect of the hepatocyte derived isoferritins. In conclusion, our findings demonstrate that acidic isoferritins with homology to immunomodulatory ferritin isoforms (p43-PLF, melanoma-derived-H-chain ferritin) are released from hepatocytes in vitro, and are able to stimulate upregulation of p53 and mediate apoptosis involving Fas (CD95) signalling as well as addressing the intrinsic mitochondrial proapoptotic pathway.
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PMID:Ferritin--a mediator of apoptosis? 1734 34