Identification of transferrin receptor in cervical and endometrial tissues

Involvement of Iron, Nuclear Factor-Kappa B (NF-κB) and Prostaglandins in the Pathogenesis of Peritoneal Endometriosis-Associated Inflammation: A Review

Peritoneal endometriosis is a chronic pelvic inflammatory disease, characterized by increased numbers of peritoneal macrophages and their secreted products such as cytokines, growth and angiogenic factors in peritoneal fluid. Inflammation plays a major role in pain and infertility associated with endometriosis, but is also extensively involved in the molecular and cellular processes that lead to peritoneal endometriotic lesion development. Several inflammatory mediators have therefore been studied in the context of endometriosis over the last few years.

The aim of this review is to focus on three that have been clearly implicated in the pathogenesis of endometriosis and may be linked: peritoneal iron metabolism, nuclear factor-kappa B (NF-κB) activation, and prostaglandin biosynthesis.

Peritoneal iron overload has been conclusively demonstrated in endometriosis patients and may induce oxidative stress in the peritoneal cavity. Oxidative stress and proinflammatory cytokines are well known to be potent activators of the NF-κB pathway, which has recently been implicated in peritoneal endometriosis. Induced NF-κB activation leads to expression of numerous proinflammatory genes such as cytokines, which may provide positive feedback to the pathway, self-perpetuating the inflammatory response. Other important NF-κB-regulated molecules are prostaglandin biosynthesis enzymes, and cyclooxygenase-2 (COX-2) in particular. Increased concentrations of prostaglandins have been evidenced in the peritoneal fluid of endometriosis patients and COX-2 inhibitors have proved to be effective in ‘in vitro’ and ‘in vivo’ experimental models.

In the light of available data collected from patient biopsies, as well as ‘in vitro’ and ‘in vivo’ studies, the respective implication and potential molecular association of iron, NF-κB and prostaglandins in the pathogenesis of endometriosis are discussed. The key role of peritoneal macrophages is emphasized and potential therapeutic targets are examined.

Aberrant expression of TfR1/CD71 in thyroid carcinomas identifies a novel potential diagnostic marker and therapeutic target

BACKGROUND

Type I receptor for transferrin (TfR1/CD71) is overexpressed in several malignant tumors, but no studies are available on thyroid carcinomas. Our previous comparative analyses of the relative distribution of transferrin in benign versus papillary thyroid carcinoma (PTC) tissues highlighted a marked malignancy-associated abundance of the molecule. The aim of the present study was to evaluate whether TfR1/CD71 is also differentially expressed in benign versus malignant thyroid tissues.

METHODS

Tissue samples, including benign lesions and follicular-derived carcinomas, from 241 patients and a total of 35 benign and malignant fresh specimens were assayed for TfR1/CD71 expression by reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry.

RESULTS

We found that transcription of TfR1/CD71 gene is constitutive in thyroid epithelia, but the mRNA is differently translated in benign and malignant tissues. Western blot revealed higher levels of TfR1/CD71 protein in malignant versus benign tissues. Immunohistochemically, most carcinomas exhibited overexpression of the receptor, predominantly in the cytoplasm of neoplastic cells. The highest expression level was detected in primary and metastatic papillary carcinomas and anaplastic carcinomas, with positive results ranging from 86% to 100% of the cases. In contrast, most benign tissues were negative, with only a minority of cases showing focal and weak immunoreactivity.

CONCLUSIONS

Our findings suggest that altered expression of TfR1/CD71 may be used as a marker helpful in distinguishing PTC from papillary hyperplasia and follicular variant PTC from benign follicular-patterned lesions. Additionally, the present observations support the rationale for the use of radiolabeled transferrin/transferrin analogs and/or anti-TfR1/CD71 antibodies for diagnostic and/or radiotherapeutic purposes in TfR1/CD71-expressing thyroid tumors.

Dihydroartemisinin Is Cytotoxic to Papillomavirus-Expressing Epithelial Cells In vitro and In vivo

Nearly all cervical cancers are etiologically attributable to human papillomavirus (HPV) infection and pharmaceutical treatments targeting HPV-infected cells would be of great medical benefit. Because many neoplastic cells (including cervical cancer cells) overexpress the transferrin receptor to increase their iron uptake, we hypothesized that iron-dependent, antimalarial drugs such as artemisinin might prove useful in treating HPV-infected or transformed cells. We tested three different artemisinin compounds and found that dihydroartemisinin (DHA) and artesunate displayed strong cytotoxic effects on HPV-immortalized and transformed cervical cells in vitro with little effect on normal cervical epithelial cells. DHA-induced cell death involved activation of the mitochondrial caspase pathway with resultant apoptosis. Apoptosis was p53 independent and was not the consequence of drug-induced reductions in viral oncogene expression. Due to its selective cytotoxicity, hydrophobicity, and known ability to penetrate epithelial surfaces, we postulated that DHA might be useful for the topical treatment of mucosal papillomavirus lesions. To test this hypothesis, we applied DHA to the oral mucosa of dogs that had been challenged with the canine oral papillomavirus. Although applied only intermittently, DHA strongly inhibited viral-induced tumor formation. Interestingly, the DHA-treated, tumor-negative dogs developed antibodies against the viral L1 capsid protein, suggesting that DHA had inhibited tumor growth but not early rounds of papillomavirus replication. These findings indicate that DHA and other artemisinin derivatives may be useful for the topical treatment of epithelial papillomavirus lesions, including those that have progressed to the neoplastic state.

Relationship between gallium 67 citrate scanning and transferrin receptor expression in lung diseases

The uptake of gallium 67 (67Ga) into cells is postulated to be through transferrin receptors (TFR) of 67Ga combined with transferrin. We studied the relationship between gallium 67 citrate scanning (67Ga scan) and immunohistochemical TFR expression in lungs of nine patients with lung cancer and eight patients with diffuse interstitial lung diseases. We found that lung cancer tissues of positive 67Ga scan expressed TFR, but those of a negative scan did not. In all of the five patients with idiopathic pulmonary fibrosis (IPF), TFR were expressed on the membrane of alveolar macrophages that formed clusters. However, TFR were not expressed in lymphocytes, neutrophils, type 2 alveolar epithelial cells, and endothelial cells. In two patients with sarcoidosis and a patient with pneumoconiosis, TFR were expressed positively only on the membrane of foamy alveolar macrophages and epithelioid cells of granuloma. These findings suggest that 67Ga-citrate initially combines with transferrin in the blood and then the complex is incorporated into cells through TFR. Therefore, 67Ga scan could be positive when cells have TFR and one should be able to observe cancer cells, clusters of alveolar macrophages, and epithelioid cells through the imaging of 67Ga scan in lung cancer and diffuse interstitial lung diseases.