N-cadherin expression in adrenal tumors: upregulation in malignant pheochromocytoma and downregulation in adrenocortical carcinoma

Potential Biomarkers of Metastasizing Paragangliomas and Pheochromocytomas

Paragangliomas and pheochromocytomas (PPGLs) are rare neuroendocrine tumors originating from paraganglionic tissue in many sites of the body. Most PPGLs are characterized by nonaggressive behavior but all of them have the potential to metastasize. PPGLs represent a great diagnostic dilemma as it is difficult to recognize tumors that are likely to be metastasizing; criteria of malignancy can be found both in benign and metastatic forms. This review aims to analyze the current knowledge of the nature of metastasizing PPGLs paying particular attention to head and neck paragangliomas (HNPGLs). Potential predictors of the malignancy risk for PPGLs were summarized and discussed. These data may also help in the development of diagnostic and prognostic strategies, as well as in the identification of novel potential therapeutic targets for patients with PPGLs.

miR-590-3p and Its Downstream Target Genes in HCC Cell Lines

miRNAs are small non-coding RNA sequences of 18-25 nucleotides. They can regulate different cellular pathways by acting on tumor suppressors, oncogenes, or both. miRNAs are mostly tissue-specific, and their expression varies depending on the cancer or the tissue in which they are found. hsa-miR-590-3p was found to be involved in several types of cancers. In this study, we identified potential downstream target genes of hsa-miR-590-3p computationally. Several bioinformatics tools and more than one approach were used to identify potential downstream target genes of hsa-miR-590-3p. CX3CL1, SOX2, N-cadherin, E-cadherin, and FOXA2 were utilized as potential downstream target genes of hsa-miR-590-3p. SNU449 and HepG2, hepatocellular carcinoma cell lines, were used to carry out various molecular techniques to further validate our in silico results. mRNA and protein expression levels of these genes were detected using RT-PCR and western blotting, respectively. Co-localization of hsa-miR-590-3p and its candidate downstream target gene, SOX2, was carried out using a miRNA in situ hybridization combined with immunohistochemistry staining through anti-SOX2. The results show that there is an inverse correlation between hsa-miR-590-3p expression and SOX2 protein expression in SNU449. Subsequently, we suggest that SOX2 can be a direct downstream target of has-miR-590-3p indicating that it may have a role in the self-renewal and self-maintenance of cancer cells. We also suggest that CX3CL1, E-cadherin, N-cadherin, and FOXA2 show a lot of potential as downstream target genes of hsa-miR-590-3p signifying its role in epithelial-mesenchymal transition. Studying the expression of hsa-miR-590-3p downstream targets can enrich our understanding of the cancer pathogenesis and how it can be used as a therapeutic tool.

The next step: mechanisms driving adrenocortical carcinoma metastasis

Endocrine tumors have the peculiarity to become clinically evident not only due to symptoms related to space occupation by the growing lesion, similarly to most other tumors, but also, and most often, because of their specific hormonal secretion, which significantly contributes to their pathological burden. Malignant endocrine tumors, in addition, have the ability to produce distant metastases. Here, we critically review the current knowledge about mechanisms and biomarkers characterizing the metastatic process in adrenocortical carcinoma (ACC), a rare endocrine malignancy with a high risk of relapse and metastatization even when the primary tumor is diagnosed and surgically removed at an early stage. We highlight perspectives of future research in the domain and possible new therapeutic avenues based on targeting factors having an important role in the metastatic process of ACC.

Phenylethanolamine N-methyltransferase downregulation is associated with malignant pheochromocytoma/paraganglioma

Malignant pheochromocytoma/paraganglioma (PCC/PGL) is defined by the presence of metastases at non-chromaffin sites, which makes it difficult to prospectively diagnose malignancy. Here, we performed array CGH (aCGH) and paired gene expression profiling of fresh, frozen PCC/PGL samples (n = 12), including three malignant tumors, to identify genes that distinguish benign from malignant tumors. Most PCC/PGL cases showed few copy number aberrations, regardless of malignancy status, but mRNA analysis revealed that 390 genes were differentially expressed in benign and malignant tumors. Expression of the enzyme, phenylethanolamine N-methyltransferase (PNMT), which catalyzes the methylation of norepinephrine to epinephrine, was significantly lower in malignant PCC/PGL as compared to benign samples. In 62 additional samples, we confirmed that PNMT mRNA and protein levels were decreased in malignant PCC/PGL using quantitative real-time polymerase chain reaction and immunohistochemistry. The present study demonstrates that PNMT downregulation correlates with malignancy in PCC/PGL and identifies PNMT as one of the most differentially expressed genes between malignant and benign tumors.

Telomerase and N-Cadherin Differential Importance in Adrenocortical Cancers and Adenomas

Adrenocortical carcinomas (ACC) are most frequently highly aggressive tumors. We assessed the telomerase reverse transcriptase (TERT) and N-cadherin role in the biology of ACC and their potential utility as molecular biomarkers, in different types of tumoral adrenocortical tissue. A total of 48 adrenal cortex samples (39 tumoral and 9 normal adrenal glands) were studied. TERT promoter mutations were searched by PCR and Sanger sequencing in two hotspots positions (-124 and -146). Also, telomerase and N-cadherin expression were evaluated by immunohistochemistry. TERT promoter mutations were not detected in any of the samples either malignant or benign. Telomerase nuclear expression was present in 26.6% of ACC and in 45.5% of non-functioning adenomas. It was absent in benign Cushing's lesions and in normal adrenal glands. Contrarily, N-cadherin was always expressed in the cellular membranes of benign adenomas or normal adrenals but no expression was detected in the majority of ACC. Nuclear telomerase and membrane N-cadherin expression were positively correlated in ACCs. We conclude that in ACC, the loss of N-cadherin is a frequent phenomenon while the existence of TERT promoter mutations is not and nuclear telomerase expression is present in only a minority of cases. Since the loss of N-cadherin expression was identified in both high and low proliferative ACC, this marker should be considered important for diagnostic application. Our study also suggests the existence of a TERT non-canonical function in cell adhesion. J. Cell. Biochem. 118: 2064-2071, 2017. © 2017 Wiley Periodicals, Inc.

Establishment of a mouse xenograft model of metastatic adrenocortical carcinoma

Adrenocortical carcinoma is a rare neoplasm with a poor prognosis. Very important advances have been made in the identification of the genetic determinants of adrenocortical carcinoma pathogenesis but our understanding is still limited about the mechanisms that determine cancer spread and metastasis. One major problem hindering preclinical experimentation for new therapies for adrenocortical carcinoma is represented by the lack of suitable animal models for metastatic disease. With the aim to overcome these limitations, in this study we tested several protocols in order to establish a mouse xenograft model of metastatic adrenocortical carcinoma. The most efficient method, based upon intrasplenic injection followed by splenectomy, produced metastases with high efficiency, whose development could be followed over time by bioluminescence measurements. We expect that the availability of this model will greatly improve the possibilities for preclinical testing of new treatments for advanced-stage disease.

Investigation of N-cadherin/β-catenin expression in adrenocortical tumors

β-catenin is a multifunctional protein; it is a key component of the Wnt signaling, and it plays a central role in cadherin-based adhesions. Cadherin loss promotes tumorigenesis by releasing membrane-bound β-catenin, hence stimulating Wnt signaling. Cadherins seem to be involved in tumor development, but these findings are limited in adrenocortical tumors (ACTs). The objective of this study was to evaluate alterations in key components of cadherin/catenin adhesion system and of Wnt pathway. This study included eight normal adrenal samples (NA) and 95 ACT: 24 adrenocortical carcinomas (ACCs) and 71 adrenocortical adenomas (ACAs). β-catenin mutations were evaluated by sequencing, and β-catenin and cadherin (E-cadherin and N-cadherin) expression was analyzed by quantitative reverse transcription PCR (qRT-PCR) and by immunohistochemistry (IHC). We identified 18 genetic alterations in β-catenin gene. qRT-PCR showed overexpression of β-catenin in 50 % of ACC (12/24) and in 48 % of ACA (21/44). IHC data were in accordance with qRT-PCR results: 47 % of ACC (7/15) and 33 % of ACA (11/33) showed increased cytoplasmic or nuclear β-catenin accumulation. N-cadherin downregulation has been found in 83 % of ACC (20/24) and in 59 % of ACA (26/44). Similar results were obtained by IHC: N-cadherin downregulation was observed in 100 % (15/15) of ACC and in 55 % (18/33) of ACA. β-catenin overexpression together with the aberrant expression of N-cadherin may play important role in ACT tumorigenesis. The study of differentially expressed genes (such as N-cadherin and β-catenin) may enhance our understanding of the biology of ACT and may contribute to the discovery of new diagnostic and prognostic tools.

Prognostic and diagnostic value of epithelial to mesenchymal transition markers in pulmonary neuroendocrine tumors

Background

Pulmonary neuroendocrine tumors (Pulmonary NETs) include a wide spectrum of tumors, from the low-grade typical carcinoid (TC) and the intermediate-grade atypical carcinoid (AC), to the high-grade large-cell neuroendocrine carcinoma (LCNEC) and the small-cell carcinoma (SCLC). Epithelial Mesenchymal Transition (EMT) is a process initially recognised during several critical stages of embryonic development, which has more recently been implicated in promoting carcinoma invasion and metastasis. The initial stage of the EMT process begins with the deregulation of adhesion molecules, such as E-cadherin, due to transcriptional repression carried out by factors such as Snail family members, Twist and Foxc2.

Methods

Immunohistochemistry for EMT markers and E-cadherin/ β-catenin complex in 134 patients with pulmonary NETs between 1990 – 2009. Analysis of potential associations with clinicopathological variables and survival.

Results

Pulmonary NETs of high malignant potential (LCNEC and SCLC) had reduced expression of the adhesion molecules and high level expression of transcriptional repressors (Snail1, Snail2, Twist and Foxc2). Snail high expression levels and the loss of E-cadherin/β-catenin complex integrity had the strongest negative effect on the five-year survival rates. E-cadherin/β-catenin complex integrity loss independently predicted lymph node involvement and helped in Atypical Carcinoid (AC) vs Typical Carcinoid (TC) differential diagnosis. Importantly, among the TC group, the loss of E-cadherin/β-catenin complex integrity identified patients with an adverse clinical course despite favourable clinicopathological features.

Conclusion

The immunohistochemical determination of E-cadherin/β-catenin complex integrity loss and EMT markers in the clinical setting might be a potential useful diagnostic and prognostic tool especially among the TC patients.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-855) contains supplementary material, which is available to authorized users.

The emerging role of the molecular marker p27 in the differential diagnosis of adrenocortical tumors

Malignant adrenocortical tumors (ACTs) are rare and highly aggressive; conversely, benign tumors are common and frequently found incidentally (the so-called incidentalomas). Currently, the use of molecular markers in the diagnosis of ACTs is still controversial. The aim of this study was to analyze the molecular profile of different ACTs with the purpose of identifying markers useful for differentiating between these tumors. The ACTs that were studied (n=31) included nonfunctioning adenomas (ACAn)/incidentalomas (n=13), functioning adenomas with Cushing's syndrome (ACAc) (n=7), and carcinomas (n=11); normal adrenal glands (n=12) were used as controls. For each sample, the percentage area stained for the markers StAR, IGF2, IGF1R, p53, MDM2, p21, p27, cyclin D1, Ki-67, β-catenin, and E-cadherin was quantified using a morphometric computerized tool. IGF2, p27, cyclin D1, and Ki-67 were the markers for which the percentage of stained area was significantly higher in carcinoma samples than in adenoma samples. Ki-67 and p27 were the markers that exhibited the highest discriminative power for differential diagnosis between carcinomas and all type of adenomas, while IGF2 and StAR were only found to be useful for differentiating between carcinomas and ACAn and between carcinomas and ACAc respectively. The usefulness of Ki-67 has been recognized before in the differential diagnosis of malignant tumors. The additional use of p27 as an elective marker to distinguish benign ACTs from malignant ACTs should be considered.

Epithelial to mesenchymal transition is activated in metastatic pheochromocytomas and paragangliomas caused by SDHB gene mutations

CONTEXT

Pheochromocytoma and paraganglioma are rare neural-crest-derived tumors. They are metastatic in 15% of cases, and the identification of a germline mutation in the SDHB gene is a predictive risk factor for malignancy and poor prognosis. To date, the link between SDHB mutations and malignancy is still missing.

OBJECTIVE

Epithelial to mesenchymal transition (EMT) is a developmental event, reactivated in cancer cells to promote cell mobility and invasiveness. The aim of this study was to address the participation of EMT in the metastatic evolution of pheochromocytoma/paraganglioma.

DESIGN AND PATIENTS

Transcriptomic profiling of EMT was performed on 188 tumor samples, using a set of 94 genes implicated in this pathway. Activation of EMT was further confirmed at protein level by immunohistochemistry in a second set of 93 tumors.

RESULTS

Hierarchical unsupervised classification showed that most SDHB-metastatic samples clustered together, indicating that EMT is differently regulated in these tumors. Major actors of EMT, metalloproteases and components of cellular junctions, were either up-regulated (LOXL2, TWIST, TCF3, MMP2, and MMP1) or down-regulated (KRT19 and CDH2) in SDHB-metastatic tumors compared with nonmetastatic ones. Interestingly, within metastatic tumors, most of these genes (LOXL2, TWIST, TCF3, MMP2, and KRT19) also allowed us to discriminate SDHB-mutated from non-SDHB-related tumors. In the second set of tumors, we studied Snail1/2 expression by immunohistochemistry and observed its specific nuclear translocation in all SDHB-metastatic tumors.

CONCLUSION

We have identified the first pathway that distinguishes SDHB-metastatic from all other types of pheochromocytomas/paragangliomas and suggest that activation of the EMT process might play a critical role in the particularly invasive phenotype of this group of tumors.

Pheochromocytomas and paragangliomas: assessment of malignant potential

Pheochromocytomas and paragangliomas (PPGLs) are rare catecholamine-secreting tumors which arise from the adrenal glands or sympathetic neuronal tissue. Malignant transformation of these tumors occurs in a significant proportion and may therefore lower overall survival rates. In patients with PPGLs it is impossible to identify malignant disease without the presence of metastatic disease, something which can occur as long as 20 years after initial surgery. Early identification of malignant disease would necessitate a more aggressive treatment approach, something which may result in better disease outcome. We have therefore reviewed possible predictors of malignancy and current developments in order to help clinicians to swiftly assess malignant potential in patients with PPGLs. Currently, there is no absolute marker which can objectively reflect malignant potential. Tumor size is the most reliable predictor and should therefore be used as the baseline characteristic. The combination of various clinical markers (extra-adrenal disease and post-operative hypertension), biochemical markers (high dopamine, high norepinephrine and epinephrine to total catecholamine ratio) and/or histological markers (SNAIL, microRNAs and/or microarray results) can raise or lower the suspicion of malignancy. Furthermore, we discuss how clinical markers may affect biochemical results linked to malignancy, how biochemical results may distinguish hereditary syndromes, the role of imaging in determining malignant potential and tumor detection, and recent results of proposed histological markers.

Malignant pheochromocytomas and paragangliomas: a diagnostic challenge

INTRODUCTION

Malignant pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare disorders arising from the adrenal gland, from the glomera along parasympathetic nerves or from paraganglia along the sympathetic trunk. According to the WHO classification, malignancy of PCCs and PGLs is defined by the presence of metastases at non-chromaffin sites distant from that of the primary tumor and not by local invasion. The overall prognosis of metastasized PCCs/PGLs is poor. Surgery offers currently the only change of cure. Preferably, the discrimination between malignant and benign PCCs/PGLs should be made preoperatively.

METHODS

This review summarizes our current knowledge on how benign and malignant tumors can be distinguished.

CONCLUSION

Due to the rarity of malignant PCCs/PGLs and the obvious difficulties in distinguishing benign and malignant PCCs/PGLs, any patient with a PCC/PGL should be treated in a specialized center where a multidisciplinary setting with specialized teams consisting of radiologists, endocrinologist, oncologists, pathologists and surgeons is available. This would also facilitate future studies to address the existing diagnostic and/or therapeutic obstacles.

Effects of dietary flavonoids, luteolin, and quercetin on the reversal of epithelial-mesenchymal transition in A431 epidermal cancer cells

Highly invasive A431-III cells, which are derived from parental A431-P cells, were originally isolated by three successive passages through a Boyden chamber using a Matrigel-coated membrane support. The greater invasion potential shown by A431-III cells was due to their increased ability to spread/migrate, which was associated with enhanced MMP activity. The tumor progression events evoked by A431-P cells compared to A431-III cells may help identify useful strategies for evaluating the epithelial-mesenchymal transition (EMT) and these cell lines could be a reliable model for evaluating tumor metastasis events. Using this approach, we evaluated the effects of luteolin and quercetin using the A431-P/A431-III EMT model. These flavonoids reversed cadherin switching, downregulated EMT markers, and nullified the invasion ability of A431-III cells. Overexpression of MMP-9 resulted in induction of the EMT in A431-P cells and this could be reversed by treating with luteolin or quercetin. Cotreatment of A431-P and A431-III cells with epidermal growth factor (EGF) plus luteolin or quercetin resulted in a more epithelial-like morphology, led to reduced levels of EGF-induced markers of EMT, and caused the restoration of cell-cell junctions. E-cadherin was decreased by EGF, but increased by luteolin and quercetin. Our results suggest that luteolin and quercetin are potentially beneficial agents that target and prevent the occurrence of EMT in epidermal carcinoma cells. These chemicals also have the ability to attenuate tumor progression in A431-III cells. Luteolin and quercetin show inherent potential as chemopreventive/antineoplastic agents and do this by abating tumor progression through a reversal of EMT.

Histologic and immunohistochemical characterization of pheochromocytoma in 6 cotton-top tamarins (Saguinus oedipus)

Pheochromocytomas are uncommon neoplasms of the adrenal medulla that are most frequently reported in rats and select mouse strains. In many cases, especially those in man, pheochromocytoma is associated with familial tumor syndromes, because of inherited mutations in a variety of proto-oncogenes and tumor suppressor genes. Nonhuman primates are valuable animal models for a variety of human diseases because of their similar anatomy and physiology; however, cases of pheochromocytomas have only rarely been reported in nonhuman primates. Herein, we characterize the gross, histologic, and immunohistochemical features of pheochromocytoma in 6 cotton-top tamarins (Saguinus oedipus). Pheochromocytomas represented 6 of 114 of the total causes of death in the studied population (5.3%) and corresponded to 16% of the total number of neoplasms. The average age of affected animals was 17.9 years. On histologic examination, all cases were defined by tight bundles, nests, and cords of neoplastic chromaffin cells. All cases had concurrent myocardial degeneration and fibrosis of varying severity and chronicity. Three of the cases (50%) also had hyalinization and medial thickening of coronary arteries consistent with hypertension. On immunohistochemical examination, 6 of 6 of the cases (100%) stained positively for chromogranin A, synaptophysin, N-CAM (or CD56), and protein gene product 9.5. None of the cases stained for glial fibrillary acidic protein. Pedigree analysis revealed inter-relatedness in 4 of 6 animals, with progenitor animals also affected with pheochromocytomas. The tumors in this population illustrate comparable histologic and immunohistochemical staining patterns with cases in other laboratory animals and humans, and, therefore, may indicate common underlying genetic alterations that precipitate tumor development.

Expression of the transcription factor snail and its target gene twist are associated with malignancy in pheochromocytomas

BACKGROUND

One of the best known functions of the zinc-finger transcription factor Snail is to induce epithelial-mesenchymal transition (EMT). Twist, a target genes of Snail, is known to promote the development of distant metastases in mice. Increasing evidence suggests that EMT plays a pivotal role in tumor progression and metastatic spread.

METHODS

Snail, Twist, and E-cadherin expression were assessed by immunohistochemistry and real-time quantitative reverse transcriptase-polymerase chain reaction in 12 malignant and 35 benign pheochromocytomas (PCC). Data were correlated with clinical characteristics and genetics.

RESULTS

We found Snail expression in 13 (28%) of 47 primary PCC samples. Twist was expressed in 31 (66%) of 47 cases. Only one of 47 PCC showed E-cadherin expression. We observed Snail expression in 7 (58%) of 12 malignant PCC, whereas only 6 (17%) of 35 apparently benign PCC revealed Snail expression (P = 0.01). Furthermore, 11 (92%) of 12 malignant PCC, but only 20 (57%) of 35 benign PCC, revealed Twist expression (P = 0.03). Interestingly, all five metastases showed Snail and Twist expression. In normal adrenal medulla, Snail, Twist, and E-cadherin expression could not be detected.

CONCLUSIONS

We describe for the first time that EMT markers Snail and Twist are expressed in PCC and that their expression is associated with malignancy. Our study supports a role for EMT in the malignant transformation of PCC.

Genetic markers for the diagnosis and prognosis of pheochromocytoma

The last 5 years have witnessed important advances in understanding the mechanisms of tumorigenesis of chromaffin cells. Large-scale microarray analyses of pheochromocytomas have identified two distinct gene-expression profiles encompassing all hereditary and sporadic tumors. Gene-expression profiling of benign and malignant pheochromocytomas is providing a better understanding of the mechanisms of metastasis. Such studies hold promise for the development of new prognostic markers for early detection of malignant pheochromocytoma and for the identification of novel targets for therapeutic intervention.

N-cadherin as a therapeutic target in cancer

During tumor progression, cancer cells undergo dramatic changes in the expression profile of adhesion molecules resulting in detachment from original tissue and acquisition of a highly motile and invasive phenotype. A hallmark of this change, also referred to as the epithelial-mesenchymal transition, is the loss of E- (epithelial) cadherin and the de novo expression of N- (neural) cadherin adhesion molecules. N-cadherin promotes tumor cell survival, migration and invasion, and a high level of its expression is often associated with poor prognosis. N-cadherin is also expressed in endothelial cells and plays an essential role in the maturation and stabilization of normal vessels and tumor-associated angiogenic vessels. Increasing experimental evidence suggests that N-cadherin is a potential therapeutic target in cancer. A peptidic N-cadherin antagonist (ADH-1) has been developed and has entered clinical testing. In this review, the authors discuss the biochemical and functional features of N-cadherin, its potential role in cancer and angiogenesis, and summarize the preclinical and clinical results achieved with ADH-1.

Malignant pheochromocytoma: state of the field with future projections

The prevalence of malignant pheochromocytoma is about 10%, and is somewhat higher for paraganglioma. A problem for clinical follow-up is that patients with "benign" histopathologic findings may develop metastatic disease. At the first international symposium on pheochromocytoma in Bethesda (2005) experts from different disciplines and patients shared their experiences, and the present knowledge of this rare disease was updated. The discussion related to future strategies for better clinical/histopathologic diagnosis and understanding of different geno- and phenotypes. Curative surgery can only seldom be performed because of multiple metastases. The main therapeutic goal is therefore often tumor reduction and control of hypertension. To date the best adjunct to surgery is radionuclide therapy using 131I-MIBG, but the background information for optimal treatment is still incomplete. Certain patients may benefit from 131I-MIBG combined with radiotherapy via somatostatin receptors expressed by the tumor, or the combination with chemotherapy. The need for future multicenter studies was emphasized. In experimental models the work on enhanced expression of amine transporters critical for radiotherapy is continued. Ongoing microarray studies will reveal novel intracellular pathways of importance for proliferation/cell cycle control, which can be inhibited by pharmacologic tools.

Effect of di-(2-ethylhexyl) phthalate on N-cadherin and catenin protein expression in rat testis

This study investigated the effect of DEHP exposure on N-cadherin and alpha-, beta- and p120-catenin immunoreactivities in the rat testis. DEHP was administered by daily gavage to 25-day-old male Sprague-Dawley rats at a dose of 2 g DEHP/5 ml corn oil/kg body weight for 2 days or 7 days. Control rats were treated with corn oil vehicle under the same conditions. Animals were killed at 24h after the last treatment. Another group of rats treated with DEHP or corn oil vehicle (control group) for 2 days were held for 30 days without treatment to observe recovery. Testes were analyzed for histopathology, TUNEL staining, immunofluorescence (IF) and Western blot analyses. Animals exposed to DEHP for 2 days or 7 days showed severe alterations of seminiferous tubules characterized by germ cell sloughing. Animals from the longer term recovery group treated with DEHP showed foci of delayed spermatogenesis. A linear and continuous pattern of N-cadherin was observed in the basal compartment of the seminiferous tubules. A similar pattern but with higher IF intensity was observed for N-cadherin in rats treated with DEHP for 2 days or 7 days, compared to control animals. The alpha-, beta- and p120-catenins were detected in the basal compartment of seminiferous tubules in similar localization and IF pattern for DEHP and control groups. A significant increase in testicular N-cadherin and alpha-catenin levels was detected by Western blot analysis in DEHP-exposed versus control rats. No variations in N-cadherin or catenin expression were detected in the recovery groups. These findings demonstrate that DEHP induces an up-regulation of N-cadherin and alpha-catenin expression and may perturb cell-cell adhesion phenomena in the seminiferous tubule.

Histopathology and immunohistochemistry of adrenal medullary tumors and paragangliomas

Paragangliomas arise from sympathetic or parasympathetic paraganglia and should now be defined by their site and type. The term pheochromocytoma is reserved for intra-adrenal tumors. This short review discusses the gross and microscopic features, the immunohistochemical profile, the problem of recognizing malignant potential, and the rare instances where a differential diagnosis has to be considered.

Autopsy case of prostate cancer with multiple endocrine neoplasia 2A

We describe an autopsy case of a 65-year-old man with prostate cancer accompanied by multiple endocrine neoplasia 2A (MEN 2A), including malignant pheochromocytomas, thyroid medullary carcinomas and parathyroid hyperplasia. Metastatic lesions from the prostate primary were identified using immunohistochemistry for prostate specific antigen within both primary and metastatic pheochromocytomas in the liver. To investigate the affinity of prostate cancer for pheochromocytoma cells, immunohistochemistry was carried out using a number of antibodies and both tumors were positive for N-cadherin. Interestingly, pheochromocytomas, thyroid medullary carcinomas and prostate cancer were all positive for the anti-RET antibody. The immunohistochemical results suggest that the cell affinity may, in part, result from cell-cell adhesion via N-cadherin. Although prostate cancer is rarely associated with MEN, RET activation may have participated in the tumorigenesis of this case.

Effects of 18beta-glycyrrhetinic acid on the junctional complex and steroidogenesis in rat adrenocortical cells

Cellular junctions play important roles in cell differentiation, signal transduction, and cell function. This study investigated their function in steroid secretion by adrenal cells. Immunofluorescence staining revealed the presence of gap junctions and adherens junctions between adrenal cells. The major gap junction protein, connexin43, was seen as a linear dotted pattern of the typical gap junction plaques, in contrast to alpha-, beta-, and gamma-catenin, which were seen as continuous, linear staining of cell-cell adherens junction. Treatment with 18beta-glycyrrhetinic acid, a gap junction inhibitor, reduced the immunoreactivity of these proteins in a time- and dose-dependent manner, and caused the gap junction and adherens junction to separate longitudinally from the cell-cell contact sites, indicating the structural interdependency of these two junctions. Interestingly, 18beta-glycyrrhetinic acid stimulated a two- to three-fold increase in steroid production in these adrenal cells lacking intact cell junctions. These data raise the question of the necessity for cell communication for the endocrine function of adrenal cells. Pharmacological analyses indicated that the steroidogenic effect of 18beta-glycyrrhetinic acid was partially mediated by extracellular signal-related kinase and calcium/calmodulin-dependent kinase, a pathway distinct from the protein kinase A signaling pathway already known to mediate steroidogenesis in adrenal cells.