Chemerin and CMKLR1 expression in human arteries and periadventitial fat: a possible role for local chemerin in atherosclerosis?

BACKGROUND: Depending on their anatomical location, different fat depots have a different capacity to produce bioactive peptides, called adipokines. Adipokines produced by periadventitial fat have been implicated in the pathogenesis of vascular disease, including atherosclerosis. Chemerin is an adipokine with an established role in immunity, adipose tissue function and metabolism, acting in autocrine, paracrine and endocrine manners. We investigated the protein expression of chemerin and its receptor, CMKLR1, in human aortas, coronary vessels and the respective periadventitial adipose tissue and correlated their expression with the presence of atherosclerosis. METHODS: Immunohistochemistry for chemerin and CMKLR1 was performed on human aortic and coronary artery samples including the periadventitial adipose tissue. Aortic and coronary atherosclerotic lesions were assessed using the AHA classification. RESULTS: Chemerin immunopositivity was noticed in both periadventitial fat depots, in vascular smooth muscle cells and foam cells in atherosclerotic lesions. Periadventitial fat and foam cell chemerin immunopositivity was statistically significantly correlated with the severity of atherosclerosis in both locations. CMKLR1 was expressed in vascular smooth muscle cells and foam cells in aortic and coronary vessels with atherosclerotic lesions. CMKLR1 immunostaining in foam cells was statistically significantly correlated with aortic atherosclerosis. CONCLUSIONS: Our results lend some support to a presumable role of locally produced chemerin in the progression of atherosclerotic lesions, possibly acting through its CMKLR1 receptor. Further research will elucidate the role of chemerin signaling in atherosclerosis.

Adiponectin/T-cadherin and apelin/APJ expression in human arteries and periadventitial fat: implication of local adipokine signaling in atherosclerosis?

INTRODUCTION: Adipose tissue is considered an endocrine organ, producing bioactive peptides, called adipokines. Adipokines produced by periadventitial fat have been implicated in the pathogenesis of vascular disease, including atherosclerosis. Adiponectin has established antiatherogenic actions, while the role of T-cadherin as an adiponectin receptor is not fully elucidated. The apelinergic system, consisting of apelin and its APJ receptor, is a mediator of various cardiovascular functions and may also be involved in the atherosclerotic process. We investigated the protein expression of adiponectin, T-cadherin, apelin and APJ in human aortas, coronary vessels, and the respective periadventitial adipose tissue and correlated their expression with the presence of atherosclerosis and clinical parameters. METHODS: Immunohistochemistry for adiponectin, T-cadherin, apelin, and APJ was performed on human aortic and coronary artery samples including the periadventitial adipose tissue. Aortic and coronary atherosclerotic lesions were assessed using the american heart association (AHA) classification. RESULTS: Adiponectin immunostaining, of varied intensity, was detected only in adipocytes, while T-cadherin was localized to vascular smooth muscle cells (VSMCs) and endothelial cells. Apelin immunostaining was detected in adipocytes, VSMCs, endothelial cells, and foam cells in atherosclerotic lesions, while APJ was found in VSMCs and endothelia. Periadventitial adiponectin and VSMC T-cadherin expression were negatively correlated with atherosclerosis in both sites, as was VSMC apelin expression. Several other - depot specific - associations were observed. CONCLUSIONS: Our results suggest a possible role for T-cadherin as a mediator of antiatherogenic adiponectin actions, while they support the putative antiatherogenic profile for apelin and its APJ receptor in human arteries. Further research is absolutely necessary to confirm these notions. SUMMARY: Periadventitial adipose tissue adipokines are implicated in vascular physiology and pathology. Adiponectin/T-cadherin and apelin/APJ immunoreactivity is detected in human aortas and coronary arteries. Adiponectin/T-cadherin and apelin/APJ expression patterns were found to be inversely associated with human aortic and coronary atherosclerosis.

Androgen receptor in laryngeal carcinoma: could there be an androgen-refractory tumor?

Androgen receptors (ARs) which are implicated in the pathogenesis of several malignancies can also be a possible downstream effector in laryngeal cancer. In the present study, 97 invasive squamous laryngeal carcinomas were studied by immunohistochemistry for protein expression of AR. Androgen receptors were expressed in 52.6% of tumor specimens, suggesting their implication in the pathogenesis of this tumor. Our study's aim was to investigate the hypothetical scenario of an androgen refractory laryngeal carcinoma where androgen receptors can be activated by nodal molecules in the course of an Epithelial-to-mesenchymal transition (EMT) phenomenon. In line with this we correlated AR expression with the expression of ILK, p-Akt, E-cadherin, ß-catenin in our sample as well as with tumor grade and TNM stage. A reverse correlation between nuclear AR and cytoplasmic ILK expression was evidenced, indicating an interaction of those molecules in laryngeal carcinoma. Finally in our material, in those carcinomas that were expressing ARs, stronger nuclear expression of the receptor was characterized by poorer cell differentiation and correlated with the acquisition of EMT features like E-cadherin loss and ß-catenin translocation raising a question whether activated ARs can drive an EMT procedure.

Sudden unexpected death from oligodendroglioma: a case report and review of the literature.

Sudden and unexpected deaths due to asymptomatic 5 primary brain tumors are extremely rare, with an incidence that ranges from 0.16 to 3.2%. Usually, such tumors are glioblastomas or, less commonly, astrocytomas. Asymptomatic oligodendrogliomas causing sudden death are hardly ever reported among medico-legal investigated cases.We report a rare case of sudden and unexpected death from a previously asymptomatic and undiagnosed, well-differentiated, grade II oligodendrogloioma (WHO classification). According to the autopsy and the microscopic findings brain edema as a result of obstruction of the cerebrospinal fluid flow due to hemorrhagic leakage of the oligodendroglioma is incriminated as the most probable physiopathological mechanism for the sudden death. Diagnosis is mainly based on the special microscopic features of the tumor cells (typical "fried-egg" appearance), interrupted by a dense network of branching capillaries. We discuss further the pathophysiological mechanisms of death and present a short review of literature.

Differential beta-catenin expression between glottic and supraglottic laryngeal carcinoma.

Glottic carcinomas present with a favorable prognosis comparing to supraglottic. This fact is mainly attributed to differences in anatomical, histological and embryological aspects. It is possible that differential molecular anatomy between the two distinct anatomical entities contributes to this clinical observation as well. The current study intended to evaluate, by immunohistochemistry in paraffin-embedded tissue samples from 97 invasive squamous laryngeal carcinomas, the possible differential expression of crucial molecules for malignant cell's function such as integrin-linked kinase, phosphorylated Akt, E-cadherin, beta-catenin, androgen receptor, estrogen receptor-beta and vimentin between glottic and supraglottic laryngeal carcinomas. We documented a correlation of supraglottic laryngeal carcinomas with high grade (p = 0.001) and enhanced tumor TNM stage (p < 0.001). The supraglottic location was correlated with the abolishment of beta-catenin from the membrane (p = 0.025). However, the diverse anatomical locations are not characterized by statistically significant differential expression of ILK, p-Akt, AR, ER-beta, E-cadherin and vimentin. Our results show that it is possible that molecular factors, such as beta-catenin, are differently expressed in glottic and supraglottic carcinomas, leading to the distinct clinical behavior of those tumors.

Adipokines in periaortic and epicardial adipose tissue: differential expression and relation to atherosclerosis.

AIM: Adipokines are protein products of adipose tissue with paracrine and endocrine actions, which have been implicated in the pathogenesis of cardiovascular disease. Locally produced adipokines, especially by periadventitial adipose tissue, may affect vascular physiology and pathology. We investigated the expression of adiponectin, visfatin, leptin and novel adipokines chemerin and vaspin in human periaortic and epicardial adipose tissue, as well as their correlation to aortic and coronary atherosclerosis. METHODS: Standard immunohistochemical staining for the adipokines was performed on samples of human periaortic, pericoronary and apical epicardial adipose tissue. Atherosclerotic lesions of the adjacent vascular wall were assessed using the AHA classification. RESULTS: Adipokines were expressed in periadventitial and apical epicardial adipose tissue and - except for adiponectin - in vascular smooth muscle cells and foam cells in atherosclerotic lesions. Aortic atherosclerosis was positively correlated with chemerin, vaspin, visfatin and leptin periaortic fat expression. Coronary atherosclerosis was positively correlated with chemerin and visfatin pericoronary fat expression. Adipose tissue adiponectin expression was negatively correlated to atherosclerosis in both locations. Expression of adipokines in apical epicardial fat was not associated with atherosclerosis. CONCLUSIONS: Our results show: a) a different expression pattern of adiponectin, visfatin, leptin, chemerin and vaspin in periaortic, pericoronary and apical epicardial adipose tissue, b) a correlation of these adipokines with either aortic or coronary atherosclerosis or both in a pattern characteristic for each adipokine and suggest that locally produced adipokines might differently affect the atherosclerotic process in different locations.

Survivin overexpression in HCC and liver cirrhosis differentially correlates with p-STAT3 and E-cadherin.

Survivin, a member of the family of inhibitor of apoptosis proteins, functions as a key regulator of apoptosis and cell proliferation. Overexpression of survivin has been implicated in several human cancers, including human hepatocellular carcinoma (HCC). Although several factors have been shown in vitro to upregulate survivin expression in cancer cells, the in vivo regulators of survivin in human hepato-carcinogenesis are largely unknown. We studied by immunohistochemistry the protein expression of survivin in relation to cyclin D1, phosphorylated signal transducer and activator of transcription 3 (p-STAT3), beta-catenin, E-cadherin and phosphorylated-Akt (p-Akt) in 69 cases of HCC and adjacent liver cirrhosis. Survivin was expressed in 63/69 (91.3%) cases of HCC and in 40/47 (85.1%) cases of liver cirrhosis. Survivin localization in HCC was exclusively nuclear, while intense cytoplasmic and low nuclear expression of survivin was observed in cases of cirrhosis. Survivin expression in HCC correlated significantly with low grade tumors, expression of cyclin D1 and p-STAT3. Expression of survivin in liver cirrhosis correlated with downregulation of E-cadherin expression. There was no significant correlation of survivin with beta-catenin or p-Akt in HCC or liver cirrhosis. In conclusion, we showed an association of nuclear survivin with well differentiated HCC, as well as with the expression of the cell cycle regulator cyclin D1. Activation of STAT3 and loss of E-cadherin but not beta-catenin or Akt pathways seem to be implicated in survivin upregulation in HCC and liver cirrhosis.

Loss of inhibitor of growth (ING-4) is implicated in the pathogenesis and progression of human astrocytomas.

Inhibitor of growth 4 (ING-4) is a tumor suppressor gene that interacts with nuclear factor-kappaB (NF-kappaB) and represses its transcriptional activity. Several lines of evidence suggest that the tumor suppressor gene ING-4, the transcription factor NF-kappaB and its target genes matrix metalloproteases MMP-2, MMP-9 and urokinase plasminogen activator (u-PA) are critically involved in tumor invasion. The aim of the present study was to investigate immunohistochemically the expression pattern of ING-4, NF-kappaB and the NF-kappaB downstream targets MMP-2, MMP-9 and u-PA in human astrocytomas from 101 patients. We found that ING-4 expression was significantly decreased in astrocytomas, and ING-4 loss was associated with tumor grade progression. Expression of p65, a NF-kappaB subunit, was significantly higher in grade IV than in grade III and grade I/II tumors, and a statistical significant negative correlation between expression of ING-4 and expression of nuclear p65 was noticed. MMP-9, MMP-2 and u-PA were overexpressed in human astrocytomas. Of note, astrocytomas of advanced histologic grades (grade III, IV) displayed significantly higher expression levels of these proteins compared to tumors of lower grades (grade I, II). Collectively, our data suggest an essential role for ING-4 in human astrocytoma development and progression possibly through regulation of the NF-kappaB-dependent expression of genes involved in tumor invasion.

Bone regulatory factors NFATc1 and Osterix in human calcific aortic valves.

BACKGROUND: Emerging evidence suggests that calcific aortic valve stenosis constitutes an active process sharing common features with atherosclerosis and bone formation. To further support this hypothesis, we investigated the expression of bone regulatory factors in calcified aortic valves. METHODS-RESULTS: Formalin-fixed, paraffin-embedded tissue samples of human aortic tricuspid valves (n=54) were used from patients undergoing valve replacement for calcific, non-rheumatic aortic stenosis. As controls, fourteen aortic tricuspid valves (n=14) were obtained at autopsy from patients without clinical and morphological aortic valve lesions. Sections from both stenotic and normal aortic valve leaflets were studied immunohistochemically. Interstitial cells in stenotic valves showed intense expression of Sox9, Runx2 and Osterix (Osx) whereas NFATc1 was expressed in interstitial and inflammatory cells. In addition, NFATc1 expression correlated significantly with Osx (r=0.458, p<0.001) and Runx2 (r=0.387, p<0.001). Finally, there was accumulation of activated interstitial cells, T lymphocytes and macrophages as well as intense neoangiogenesis in pathological leaflets. CONCLUSIONS: The presence of NFATc1 and Osx in our material lends further support to the hypothesis that during the process of aortic valve calcification there is expression of osteoblastic phenotypes by valvular cells.

Estrogen receptor-beta expression in human laryngeal carcinoma: correlation with the expression of epithelial-mesenchymal transition specific biomarkers.

Laryngeal carcinoma is a malignancy of the respiratory tract with a significantly higher male to female ratio, suggesting involvement of gender-depended factors in the pathogenesis. Estrogen influences the pathological processes of hormone-dependent cancers, such as breast, prostate and ovarian cancers, through its receptors, estrogen receptor-alpha (ER-alpha) and -beta (ER-beta). While ER-alpha promotes cell proliferation, recent studies indicate that ER-beta is protective against carcinoma progression into an invasive state. However, it is unclear whether ER-beta plays a role in laryngeal cancer. In the present study we examined the expression of ER-beta in 80 invasive human squamous laryngeal carcinomas by immunohistochemistry and correlated ER-beta expression with markers of epithelial-mesenchymal transition (EMT). ER-beta was expressed in 83% of tumour specimens where it was localized in the nuclei of tumour cells. The expression of ER-beta correlated positively with the maintenance of E-cadherin and beta-catenin at cell junctions and negatively with the loss of E-cadherin, nuclear translocation of beta-catenin and increased TNM stage. We concluded that estrogen receptor-beta expression is documented in laryngeal cancer indicating a possible role in the pathogenesis of this malignancy. It is suggested that ER-beta could protect tumour cells from acquiring aggressive EMT features such as E-cadherin downregulation and nuclear beta-catenin activation.

Estrogen signaling in colorectal carcinoma microenvironment: expression of ERbeta1, AIB-1, and TIF-2 is upregulated in cancer-associated myofibroblasts and correlates with disease progression.

Epidemiological and molecular data suggest the involvement of estrogen signaling in colorectal tissue, mediated mainly through estrogen receptor beta (ERbeta). Estrogens may mediate their effects in epithelial cells indirectly by acting on stromal cells. Expression of ERalpha, ERbeta1, and the ER coregulators, amplified in breast cancer-1 (AIB-1) and transcriptional intermediary factor 2 (TIF-2), was evaluated in myofibroblasts of 107 colorectal carcinomas, 77 paired samples of normal mucosa, and 29 adenomas by immunohistochemistry. Double immunostaining with a-SMA was used to identify the myofibroblasts of normal tissue, adenomas, and cancer microenvironment. ERalpha was not expressed in stromal cells. Nuclear expression of ERbeta1, AIB-1, and TIF-2 in myofibroblasts gradually increased from normal mucosa, through adenomas, to carcinomas. Cytoplasmic ERbeta1 and TIF-2 expression was enhanced in carcinomas compared to normal mucosa and adenomas. Enhanced nuclear and cytoplasmic ERbeta1 expression and elevated nuclear AIB-1 expression were more frequently noted in myofibroblasts of carcinomas of advanced stage. ERbeta1 expression in cancer-associated myofibroblasts correlated to AIB-1 and TIF-2 expression. None of the markers correlated with patients' prognosis. Our findings imply that ERbeta1-dependent (genomic and non-genomic) and ER-coregulator-dependent (AIB-1, TIF-2) signal transductions in myofibroblasts may be involved in the initiation and progression of colorectal carcinomas.

Overexpression of hedgehog pathway molecules and FOXM1 in non-small cell lung carcinomas.

The hedgehog (HH)-signaling pathway is implicated in developmental processes and its aberrant activation in adult tissues has been associated with malignancy. The aim of this study was to determine the expression pattern of HH-signaling molecules in non-small cell lung carcinomas (NSCLC), as well as the involvement of the transcription factor FOXM1, that controls cell proliferation, in this process. Paraffin-embedded tissue sections of 80 NSCLC cases and adjacent non-neoplastic lung parenchyma were immunohistochemically analyzed with anti-SHH, anti-Patched1 (PTCH1), anti-Smoothened (SMO), anti-GLI1, anti-GLI2 and anti-FOXM1 antibodies. Correlations of HH molecules with clinicopathological parameters and FOXM1 expression were evaluated. All the HH-signaling molecules examined were overexpressed in NSCLC compared with the adjacent non-neoplastic lung parenchyma. HH pathway activity and expression of PTCH1 and SMO were significantly higher in squamous cell carcinomas compared to other NSCLC histological types. Activation of HH pathway and PTCH1 expression were correlated with tumor grade being higher in low grade tumors. There was a significant correlation of lymph node metastases with expression of SMO in all NSCLC histological types and with nuclear GLI1 immunolocalization only in adenocarcinomas. Overexpression of FOXM1 in NSCLC was also significantly correlated with PTCH1, SMO and GLI1 expression. In conclusion, HH-signaling pathway is activated in NSCLC and correlates with histological type, prognostic parameters of the tumors as well as with the increased expression of FOXM1.

Expression of adiponectin and adiponectin receptors in human pituitary gland and brain.

BACKGROUND/AIMS: Adiponectin and its receptors, AdipoR1 and AdipoR2, constitute integral components of energy homeostatic mechanism in peripheral tissues. Recent studies have implicated adiponectin in central neural networks regulating food intake and energy expenditure. The present study aimed at investigating the possible expression and distribution of adiponectin and its receptors in human pituitary gland, hypothalamus and different brain areas. METHODS: Sections of the pituitary gland, hypothalamus and adjacent basal forebrain area, cerebrum and cerebellum from 35 autopsy cases, were examined using HE, PAS-Orange G, luxol fast blue/cresyl violet stains and single and double immunohistochemistry using adiponectin, AdipoR1, AdipoR2, choline acetyltransferase, FSH, LH, TSH, GH, ACTH and prolactin-specific antibodies. Age and BMI mean values +/- SD of the autopsy cases were 56 +/- 18 years and 27 +/- 5 kg/m(2), respectively. RESULTS: Strong adiponectin expression was observed in pituitary gland. In pars distalis (PD), adiponectin localized in GH, FSH, LH and TSH-producing cells and in pars tuberalis (PT) in FSH, LH and TSH-producing cells. Strong to moderate expression of AdipoR1 and AdipoR2 was observed in PD by the same cell types as adiponectin. No immunoreactivity for adiponectin receptors was noted in cells of PT. Intense AdipoR1 immunostaining was observed in neurons of lateral hypothalamic area and of nucleus basalis of Meynert (NBM). CONCLUSIONS: Adiponectin and its receptors expression in human pituitary might indicate the existence of a local system, modulating endocrine axes. Furthermore, the presence of AdipoR1 in hypothalamus and NBM suggests that adiponectin may participate in central neural signaling pathways controlling energy homeostasis and higher brain functions.

Expression of estrogen receptor co-regulators NCoR and PELP1 in epithelial cells and myofibroblasts of colorectal carcinomas: cytoplasmic translocation of NCoR in epithelial cells correlates with better [corrected] prognosis.

Proline-, glutamic acid-, and leukine-rich protein (PELP1) is a novel co-regulatory protein that modulates genomic and non genomic actions of estrogen receptors. Nuclear receptor co-repressor (NCoR) represses estrogen-receptor-dependent transcription. PELP1 and NCoR expression was evaluated in tissue sections from 107 formalin-fixed, paraffin-embedded colectomy specimens. Normal mucosa and adenomas were also evaluated in 77 and 29 cases, respectively. PELP1 was expressed in a dot-like pattern in the nuclei of epithelial and stromal cells. Statistical analysis revealed an increase in PELP1 expression in myofibroblasts from normal mucosa through adenomas to carcinomas. NCoR was expressed in the nuclei and the cytoplasm of epithelial cells. Nuclear expression was more common in normal mucosa, whereas cytoplasmic expression was higher in malignant epithelial cells. Additionally, NCoR was expressed in the cytoplasm of cancer-associated myofibroblasts, but was rarely noted in myofibroblasts of normal mucosa or adenomas. Cytoplasmic expression of NCoR in epithelial cells correlated with better disease-free and overall survival on univariate analysis and was an independent prognostic marker for disease-free survival on multivariate analysis. These findings suggest that deregulation of co-regulators expression in both epithelial cells and myofibroblasts may contribute to the initiation and progression of colorectal carcinoma.

ILK overexpression in human hepatocellular carcinoma and liver cirrhosis correlates with activation of Akt.

Hepatocellular carcinoma (HCC) is one of the most common life-threatening malignancies in the world. The molecular mechanisms leading to the development of HCC are complex and only recently have they begun to be clarified. Integrin linked-kinase (ILK), a multifunctional signaling and scaffold protein of focal adhesion plaques, has been implicated in the pathogenesis of several human malignancies. In the current study the expression of ILK, beta-catenin and E-cadherin and the phosphorylation of Akt were studied by immunohistochemistry in 69 human HCCs and adjacent normal and cirrhotic liver parenchyma. ILK and phosphorylated-Akt (p-Akt) immunostaining was observed in 100 and 79.7% of HCCs, respectively, and their protein levels correlated significantly. Activation of beta-catenin and downregulation of E-cadherin were frequently observed in HCC, but they were not related to ILK expression. A strong correlation between ILK expression and phosphorylation of Akt was also observed in cirrhotic liver. Moreover, downregulation of E-cadherin and membranous beta-catenin were found in cirrhotic tissue suggesting their involvement in the liver tissue remodeling observed in cirrhosis. Our results indicate that ILK overexpression during liver oncogenesis and cirrhosis correlates with activation of Akt but not with other conventional ILK targets.

Integrin-linked kinase cytoplasmic and nuclear expression in laryngeal carcinomas.

Integrin-linked kinase (ILK) has been implicated in the development and progression of several human malignancies. Previous in vitro studies also implicate ILK in the activation of Akt and beta-catenin as well as in the regulation of E-cadherin expression. However, the role of ILK in human laryngeal cancer and its possible in vivo downstream effectors in the disease are currently unknown. We examined by immunohistochemistry the protein expression of ILK, phosphorylated-Akt (p-Akt), E-cadherin, and beta-catenin in 97 invasive squamous laryngeal carcinomas. Increased cytoplasmic and nuclear expression of ILK and p-Akt decreased membranous expression of E-cadherin and nuclear accumulation of beta-catenin was found in 87.6%, 85.6%, 71.1%, and 43.3% of cases, respectively. Our results suggest that ILK expression may be implicated in human laryngeal carcinoma and its localization in the nucleus possibly proposes novel nuclear functions of this molecule. In addition, enhanced ILK expression correlates with activation of Akt but not with downregulation of E-cadherin and activation of beta-catenin. Finally, in our material while activated Akt seems to characterize well-differentiated tumors, loss of E-cadherin and activation of beta-catenin correlated with high grade carcinomas.

p75 and TrkC neurotrophin receptors demonstrate a different immunoreactivity profile in comparison to TrkA and TrkB receptors in human normal pituitary gland and adenomas.

BACKGROUND/AIMS: Recent knowledge indicates that neurotrophins play a significant role in neuroendocrine systems through their specific receptors TrkA, TrkB, TrkC and low-affinity p75(NTR) receptor. TrkA and TrkB receptors have been previously detected in numerous endocrine cells in human anterior pituitary and adenomas. In the present study, the localization of p75(NTR) and TrkC along with TrkA and TrkB receptors was investigated. METHODS: Semi-serial paraffin-embedded sections of 5 human normal pituitaries and 30 adenomas were immunostained using specific antibodies. RESULTS: Expression of p75(NTR) receptor was demonstrated in the intricate capillary and reticulin network in the anterior pituitary and in the pericapillary tissue and pituicytes in the posterior lobe. p75(NTR) immunoreactivity was absent from all adenomas. In normal anterior pituitary, a few scattered cells showed weak TrkC immunoreactivity in contrast to a high percentage of endocrine cells distributed throughout the pars distalis and pars intermedia which exhibited strong TrkA and/or intermediate TrkB immunoreactivity. Double immunohistochemistry demonstrated TrkA immunoreactivity in more than 80% of lactotropes and 70% of corticotropes and to a lesser extent in other cell types. Furthermore, in the majority of adenomas, independently of type, sex and age, a high percentage of TrkA- and/or TrkB-positive cells was detected. Interestingly, TrkC expression appeared to be increased in some adenomas compared to normal pituitary. Endothelial cells and perivascular connective tissue were always TrkB-immunostained. CONCLUSION: The above findings support a potential role of all neurotrophins, through their different receptors, in pituitary functions.

Neurotrophin receptors expression and JNK pathway activation in human astrocytomas.

BACKGROUND: Neurotrophins are growth factors that regulate cell growth, differentiation and apoptosis in the nervous system. Their diverse actions are mediated through two different transmembrane - receptor signaling systems: Trk receptor tyrosine kinases (TrkA, TrkB, TrkC) and p75NTR neurotrophin receptor. Trk receptors promote cell survival and differentiation while p75NTR induces, in most cases, the activity of JNK-p53-Bax apoptosis pathway or suppresses intracellular survival signaling cascades. Robust Trk activation blocks p75NTR -induced apoptosis by suppressing the JNK-p53-Bax pathway. The aim of this exploratory study was to investigate the expression levels of neurotrophin receptors, Trks and p75NTR, and the activation of JNK pathway in human astrocytomas and in adjacent non-neoplastic brain tissue. METHODS: Formalin-fixed paraffin-embedded serial sections from 33 supratentorial astrocytomas (5 diffuse fibrillary astrocytomas, WHO grade II; 6 anaplastic astrocytomas, WHO grade III; 22 glioblastomas multiforme, WHO grade IV) were immunostained following microwave pretreatment. Polyclonal antibodies against TrkA, TrkB, TrkC and monoclonal antibodies against p75NTR and phosphorylated forms of JNK (pJNK) and c-Jun (pc-Jun) were used. The labeling index (LI), defined as the percentage of positive (labeled) cells out of the total number of tumor cells counted, was determined. RESULTS: Moderate to strong, granular cytoplasmic immunoreactivity for TrkA, TrkB and TrkC receptors was detected in greater than or equal to 10% of tumor cells in the majority of tumors independently of grade; on the contrary, p75NTR receptor expression was found in a small percentage of tumor cells (approximately 1%) in some tumors. The endothelium of tumor capillaries showed conspicuous immunoreactivity for TrkB receptor. Trk immunoreactivity seemed to be localized in some neurons and astrocytes in non-neoplastic tissue. Phosphorylated forms of JNK (pJNK) and c-Jun (pc-Jun) were significantly co-expressed in a tumor grade-dependent manner (p < 0.05). Interestingly, a statistically significant (p < 0.05) reverse relationship between Trk receptors LIs and pc-Jun/pJNK LIs was noted in some glioblastomas multiforme. CONCLUSION: In the context of astrocytomas, Trk receptors (TrkA, TrkB, TrkC) expression may promote tumor growth independently of grade. Furthermore, activation of JNK pathway may contribute to progression towards malignancy. Considering the fact that regional tumor heterogeneity may be a limiting factor for immunohistochemical studies, the significance of the reverse relationship between Trk receptors and pc-Jun/pJNK LIs with respect to biological behavior of human astrocytomas requires further evaluation.

Prognostic significance of TGFbeta-1 and pSmad2/3 in breast cancer patients with T1-2,N0 tumours.

BACKGROUND: The transforming growth factor beta (TGFbeta) signaling pathway has been shown to exert divergent effects and to cross-talk with estrogen pathways in mammary gland tumorigenesis. TGF signaling in early stage breast cancer was investigated by examining the expression of TGFbeta-1 and the signaling mediators pSmad2/3 and Smad4. Their association with oestrogen and progesterone receptors, as well as with clinical and pathological features was also analyzed. PATIENTS AND METHODS: Sixty-one tumor specimens from surgically treated patients with primary T12,N0 breast cancer were examined. The expression of TGFbeta-1, pSmad2 and Smad4 was assessed implementing immunohistochemical assays. RESULTS: TGFbeta-I, pSmad2/3 and Smad4 were expressed in 50.9%, 74.0% and 61.0% of specimens, respectively. The degree of expression of the three molecules was significantly associated with each other. Loss of pSmad2/3 expression indicated a shorter disease-free survival in all patients, including those with oestrogen receptor-positive tumors. Patients not expressing TGFbeta-1 were 4.6 times more likely to experience distant recurrence. CONCLUSION: Our results demonstrate that pSmad2/3 and TGFP-1 may be promising novel prognostic markers for T1.2,N0 breast carcinomas.

Expression of p75NTR and Trk neurotrophin receptors in the enteric nervous system of human adults.

Recent evidence suggests that the expression of p75NTR and Trk neurotrophin receptors is essential for neuronal survival, not only during development, but also in adulthood. The aim of the present study was to investigate the cell localization and distribution of p75NTR and Trk receptors in the normal adult human enteric nervous system (ENS) using double-label immunohistochemistry. Immunoreactivity for p75NTR was observed in a few neurons, whereas Trk immunoreactivity was present in a higher percentage of neurons. Strong expression of both types of neurotrophin receptors was found in the enteric glia. In addition, Trk immunoreactivity was localized to nerve endings in the lamina propria, muscularis mucosa and along or between circular and longitudinal smooth muscle layers, as well as to the enteric epithelium. Furthermore, polynuclear cells, mast cells and folliculoreticular cells in the germinal layer of lymph nodes displayed p75NTR and/or Trk immunopositivity. Expression of neurotrophin receptors in an inflammatory tissue sample was much more intense compared with that of normal tissue samples. These results suggest that neurotrophin receptors, through interactions with neurotrophins, may play a critical role in functional integrity of the ENS during adulthood.