Search

PDF file 1160K, AM is a growth factor survival for LECs

PDF file 114K, described the legends of all the supplementary figures

Purpose: To study the role of the adrenomedullin system [adrenomedullin and its receptors (AMR), CLR, RAMP2, and RAMP3] in prostate cancer androgen-independent growth.Experimental Design: Androgen-dependent and -independent prostate cancer models were used to investigate the role and mechanisms of adrenomedullin in prostate cancer hormone-independent growth and tumor-associated angiogenesis and lymphangiogenesis.Results: Adrenomedullin and AMR were immunohistochemically localized in the carcinomatous epithelial compartment of prostate cancer specimens of high grade (Gleason score >7), suggesting a role of the adrenomedullin system in prostate cancer growth. We used the androgen-independent Du145 cells, for which we demonstrate that adrenomedullin stimulated cell proliferation in vitro through the cAMP/CRAF/MEK/ERK pathway. The proliferation of Du145 and PC3 cells is decreased by anti-adrenomedullin antibody (αAM), supporting the fact that adrenomedullin may function as a potent autocrine/paracrine growth factor for prostate cancer androgen-independent cells. In vivo, αAM therapy inhibits the growth of Du145 androgen-independent xenografts and interestingly of LNCaP androgen-dependent xenografts only in castrated animals, suggesting strongly that adrenomedullin might play an important role in tumor regrowth following androgen ablation. Histologic examination of αAM-treated tumors showed evidence of disruption of tumor vascularity, with depletion of vascular as well as lymphatic endothelial cells and pericytes, and increased lymphatic endothelial cell apoptosis. Importantly, αAM potently blocks tumor-associated lymphangiogenesis, but does not affect established vasculature and lymphatic vessels in normal adult mice.Conclusions: We conclude that expression of adrenomedullin upon androgen ablation in prostate cancer plays an important role in hormone-independent tumor growth and in neovascularization by supplying/amplifying signals essential for pathologic neoangiogenesis and lymphangiogenesis. Clin Cancer Res; 19(22); 6138–50. ©2013 AACR.

PDF file 97K, AM induced activation of MAPK pathway and Normal Vascularization is not disrupted by {alpha}AM treatment

The microRNA-200 (miR-200) family is frequently down-regulated in tumors, including pancreatic adenocarcinomas (PDACs). In this study we have examined the mechanisms involved in the loss of miR-200s in tumoral pancreatic cells. Whereas miR-200 gene promoters appear methylated in mature miR-200 deficient cell lines, miR-200 precursors are detected in nuclear but not cytoplasmic compartment of these cells, indicating that promoter hypermethylation is not sufficient to explain the deficit of mature miR-200s. The ribonuclease Monocyte Chemotactic Protein-induced Protein-1 (MCPiP1) may counteract Dicer1 in miRNA maturation process. MCPiP1/Dicer1 mRNA and protein ratios appear higher in miR-200 deficient compared to miR-200 proficient cells, suggesting that MCPiP1 may compete with Dicer1 in mature miR-200 deficient cells. Inhibition of MCPiP1 allows the detection of miR-200 precursors in cytoplasm of miR-200 deficient cells, confirming its involvement in the loss of miR-200s. Also, reversion of MCPiP1/Dicer1 ratio by over-expression of Dicer1 in miR-200 deficient cells leads to the recovery of mature miR-200s. Finally, whereas human malignant pancreatic tissues (PDACs) express lower miR-200 levels than non malignant tissues (non-MPDs), MCPiP1/Dicer1 ratio appears higher in PDACs, when compared to non-MPDs, supporting the hypothesis that MCPiP1/Dicer1 ratio is determinant in regulating miR-200 maturation process in a subset of tumoral pancreatic cells.

Glioblastoma multiforme (GBM) is the most common primary brain tumor and is among the deadliest of human cancers. Dysregulation of microRNAs (miRNAs) expression is an important step in tumor progression as miRNAs can act as tumor suppressors or oncogenes and may affect cell sensitivity to chemotherapy. Whereas the oncogenic miR21 has been shown to be overexpressed in gliomas, the expression and function of the tumor-supressor miR200a in GBMs remains unknown. In this study, we show that miR21 is upregulated in grade IV (GBMs) vs. grade II-III (LGs) gliomas, confirming that miR21 expression level is correlated with tumor grade, and that it may be considered as a marker of tumor progression. Conversely, miR200a is demonstrated for the first time to be downregulated in GBMs compared with LGs, and overexpression of miR200a in GBM cells is shown to promote TMZ-sensitivity. Interestingly, miR200a but not miR21 expression level is significantly higher in TMZ-responsive vs. -unresponsive tumoral glial cells in primary culture. Furthermore, miR200a appears negatively correlated with the expression of the DNA repair enzyme O (6)-methylguanine methyltransferase (MGMT), and the inhibition of MGMT activity results in an increase of miR200a expression in GBM cells. Taken together, these data strongly suggest that miR200a is likely to act as a crucial antitumoral factor regarding glioma progression. Interplay between miR200a and MGMT should be considered as potential mechanism involved in therapeutic response.

Glioblastoma remains the most frequent and aggressive primary brain tumor in adults and is characterized by extensive angiogenesis.1 Recently, bevacizumab, a monoclonal antibody against vascular endothelial growth factor A (VEGFA), was associated with valuable, but heterogeneous, activity in patients with recurrent high-grade gliomas.2,3 In addition to the standard of care for newly diagnosed glioblastoma, the use of bevacizumab as a first-line treatment has been associated with prolonged progression-free survival (PFS) and maintenance of functional independence, but no difference has been observed in overall survival (OS).4,5 Given this heterogeneous activity and the uncertain impact on OS, a predictive biomarker of bevacizumab activity remains an unmet medical need. In this context, we recently reported that before bevacizumab administration, a baseline of high and low plasma levels of MMP2 and MMP9, respectively, were associated with a high response rate and prolonged PFS and OS in recurrent high-grade gliomas treated with bevacizumab.6 Moreover, we did not observe any correlation between these 2 biomarkers and the survival of patients when the plasma levels were measured before administration of cytotoxic agents without antiangiogenic therapy, suggesting a predictive—rather than a prognostic—value of the biomarkers.6 Considering the potential role of biomarkers in treatment monitoring, it is of interest to analyze the successive change in the plasma levels of these markers during bevacizumab treatment. We retrospectively included all patients with recurrent high-grade gliomas who had been referred to both of our institutions (APHM, Marseille, and APHP, Paris). They were treated with a combination of bevacizumab (10 mg/kg on days 1 and 15) and irinotecan until progression, and their plasma samples at each cycle and at progression were available as part of the ongoing studies (APHM Tumor Bank, authorization number 2013–1786). Plasma samples were collected before bevacizumab administration and then every 14 days, on day 1 and day 15 (before bevacizumab administration) of each cycle until progression. All patients provided written informed consent in accordance with our institutional and national guidelines and the Declaration of Helsinki. The plasma levels of MMP2 and MMP9 were assessed using ELISA kits (R&D Systems). Changes were analyzed using the paired-samples t test, and correlations were analyzed using the Spearman test. Forty-one patients were included. Patient and treatment characteristics are reported in Table 1. The plasma level of MMP2 significantly increased during bevacizumab treatment from baseline (B) to the last point prior to progression (PTP) (P = .001) and decreased at the time of progression (P) (P = .033); B, PTP, and P mean plasma levels of MMP2 were 210.4 ng/mL, 245.9 ng/mL, and 220.4 ng/mL, respectively (Fig. 1). In contrast, the plasma level of MMP9 decreased during bevacizumab treatment (P = .034) and tended to increase at P (not significant); B, PTP, and P mean plasma levels of MMP9 were 194.6 ng/mL, 113.0 ng/mL, and 151.0 ng/mL, respectively. Finally, the plasma levels of MMP2 and MMP9 were inversely correlated at B and at P (P < .001 and P = .011, respectively). A trend was observed at the last cycle before progression (P = .065). Table 1. Patient characteristics at the time of bevacizumab + irinotecan administration Fig. 1. Variations of MMP2 (A) and MMP9 (B) mean plasma levels during bevacizumab treatment from baseline until progression. In this retrospective bicentric study, we showed that the plasma level of MMP2, and to a lesser extent that of MMP9, varied during treatment and at the time of progression. We previously reported that these markers could potentially allow initial patient selection for treatment.6 In the present study, the change in the levels of these biomarkers provided additional information on tumor response events during bevacizumab treatment. In particular, considering the challenge of assessing progression during the bevacizumab treatment, the decrease in the plasma levels of MMP2 observed at P suggests that this biomarker can help in monitoring bevacizumab treatment. This predictive value, observed at B in our previous work and at P in the present study demonstrating the changes observed during bevacizumab treatment, reinforces the potential value of these markers and the need of their assessment in a prospective trial. Variations in the plasma levels of MMP2 were previously reported for the multitargeted antiangiogenic tyrosine kinase inhibitor cediranib.7 In a phase 2 trial conducted in patients with recurrent glioblastoma, the use of cediranib induced a transient decrease in the plasma level of MMP2 between 8 and 24 hours after the first administration. While the baseline level of MMP2 had no impact on patient outcome, the increase in the plasma level of MMP2 8 hours after the administration of cediranib was associated with a reduced PFS and OS. The plasma level of MMP9 at B and changes during treatment were not correlated to patient outcome. It is not known if these differences in variations and impact are related to the differences in the activity or the mechanism of action between cediranib and bevacizumab. Finally, MMP2 and MMP9 appeared to be inversely correlated at both B and P. This inverse correlation suggests a biological interaction of these 2 proteases in the tumor vascularization process and is in line with their inverse predictive values that were also observed at B.6 MMP2 was reported to be particularly implicated in angiogenesis through the promotion of VEGFA expression and its coexpression with VEGFR2.8,9 Indeed, in the absence of MMP2 expression, tumor vessel density as well as VEGFA and VEGFR2 expressions decreased dramatically, suggesting an important role of MMP2 in the angiogenic process. In contrast, MMP9 is required for tumor vasculogenesis but not for angiogenesis.10 Indeed, MMP9 appeared to be particularly implicated in the recruitment of circulating endothelial and myeloid precursors, an alternative vascularization process that was in part independent of the VEGF pathway.10 This study on MMP2 and MMP9 changes during bevacizumab treatment provides additional support for considering the potential value of these biomarkers in predicting bevacizumab activity in patients with high-grade glioma. Adequate prospective studies in this regard are warranted.

Adrenomedullin (AM) is a multifunctional peptide vasodilator that transduces its effects through calcitonin receptor-like receptor/receptor activity modifying protein-2 and -3 (CLR/RAMP2 and CLR/RAMP3). Previously, we reported on the development of an anti-AM antibody that potently inhibits tumor cell proliferation in vitro and tumor growth in vivo. Here, we report the effect of anti-AM receptor antibodies (alphaAMRs) on angiogenesis and tumor growth. We demonstrate that alphaAMRs decrease in a dose-dependent manner the growth of U87 glioblastoma cells and HT-29 colorectal cancer cells, but not A549 lung cancer cells, in vitro. In vivo, AM in Matrigel plugs induces angiogenesis by promoting recruitment of endothelial cells, pericytes, myeloid precursor cells, and macrophages and by promoting channel formation. Remarkably, systemic administration of alphaAMRs every 3 d markedly reduced neovascularization of Matrigel plugs in a dose-dependent fashion, as demonstrated by reduced numbers of the recruited cells and vessel structures. Several human tumor xenografts in athymic mice were used to examine the effect of alphaAMR treatment on tumor angiogenesis and growth. AlphaAMR treatment significantly suppressed the growth of glioblastoma, lung, and colon tumors. Histological examination of alphaAMR-treated tumors showed evidence of disruption of tumor vascularity with decreased microvessel density, depletion of endothelial and pericyte cells, and increased tumor cell apoptosis. These findings support the conclusion that alphaAMR treatment inhibits tumor growth by suppression of angiogenesis and tumor growth and suggest that AMRs may be useful therapeutic targets.

Resume La glande prostatique est androgenodependante. L’implication des androgenes dans le developpement, la fonction et la pathologie de la glande prostatique (hypertrophie benigne ou HBP, cancer), peut etre examinee de deux manieres : Soit au travers de donnees directes, issues des modeles experimentaux (in vitro–in vivo) ou de l’analyse biologique des tissus prostatiques humains normaux et pathologiques qui permettent de decrire les mecanismes moleculaires, cellulaires et tissulaires mis en jeu ; soit au travers de donnees indirectes issues des etudes epidemiologiques et cliniques, de suppression, ou supplementation androgenique decrivant l’impact sur la glande prostatique. Sur le plan experimental, il est generalement admis que la croissance de la prostate est regulee par les androgenes (testosterone et ses metabolites actifs). Un niveau approprie de testosterone circulante est necessaire pour maintenir la croissance, le developpement, la differenciation et la fonction de la glande prostatique. L’orchidectomie bilaterale induit la mort cellulaire programmee (apoptose) et l’involution de la glande ; l’administration de testosterone exogene est alors capable d’induire la croissance prostatique jusqu’au niveau normal. Il en va de meme lorsqu’on traite un animal impubere. La reponse de la prostate a la testosterone exogene ne produit donc pas une croissance au-dela du volume normal qui est maintenu par l’equilibre entre proliferation et mort cellulaire en presence de niveaux physiologiques d’androgenes. L’etude des mecanismes de regulation de la croissance prostatique donne une justification fondamentale aux traitements medicamenteux et hormonaux utilises par les urologues dans le traitement de l’HBP du cancer de prostate. Dans le cadre du deficit androgenique lie a l’âge (DALA), il persiste un doute sur une action potentiellement nefaste du traitement androgenique substitutif sur la prostate.

BACKGROUND: Predictive marker of bevacizumab activity is an unmet medical need. We evaluated predictive value of selected circulating prebiomarkers involved in neoangiogenesis and invasion on patient outcome in recurrent high grade glioma (HGG) treated with bevacizumab. METHODS: A set of eleven prebiomakers of interest (VEGF, VEGF-R2, bFGF, SDF1, PlGF, uPA, PAI1, MMP2, MMP7, MMP9, and adrenomedulline) were analyzed in plasma, using ELISA, at baseline and 2 weeks apart from bevacizumab initiation in a prospective cohort of 26 patients (Cohort1). Correlations were validated in a separate retrospective cohort (Cohort2;n = 50) and tested in cohort patients treated with cytotoxic agents without bevacizumab (Cohort3;n = 34). Dosages were correlated to objective response (OR), Progression-free survival (PFS), and overall survival (OS). In cohort 1, multiple time points were performed up to progression. Additionally MMP2 and MMP9 plasma levels were analyzed in patients with newly diagnosed GB, after surgery. Finally, MMP2 and 9 RNA were assessed in tumor tissue of a separated group of paired newly diagnosed and recurrent GB (n = 29). RESULTS: In cohort1, high MMP2 baseline level was associated to a probability of OR of 83.3% versus 15.4% in case of low MMP2 level (p = 0.001). In multivariate analysis, baseline level of MMP2 correlated with PFS (hazard-ratio(HR), 3.92; 95% confidence-interval(CI):1.46-10.52; p = 0.007) and OS (HR, 4.62; 95%CI 1.58-13.53; p = 0.005), as decrease of VEGF (p = 0.038 for PFS and p = 0.013 for OS) and MMP9 (p = 0.016 for PFS and p= 0.025 for OS). In cohort2, MMP2, but not MMP9, confirmed its predictive significance. In cohort3, no association was found between MMP2, MMP9 and outcome. In cohort 1, significant changes in MMP2 and MMP9 plasma levels were observed during treatment. MMP2 increased after Bev initiation (p = 0.002), and decreased at progression (p = 0.002) while MMP9 initially decreased (p = 0.007) then increased at progression (p = 0.031). No significant difference was observed both for plasma level and tissue RNA expression between newly diagnosed and recurrent GB. CONCLUSIONS: In patients with recurrent HGG treated with bevacizumab, but not with cytotoxic agent, high MMP2 plasma levels are associated with prolonged tumor control and survival, while changes over time may reflect tumor control. Comparison of MMP2/MMP9 levels between initial diagnosis and recurrence may suggest that bevacizumab could be similarly effective in this two setting. MMP2 should be tested in randomized clinical trials that evaluate bevacizumab efficacy, and its biological role reassessed. SECONDARY CATEGORY: Clinical Neuro-Oncology.

Glioblastoma multiforme (GBM) is the most common primary brain tumor and is among the deadliest of human cancers. Dysregulation of microRNAs (miRNAs) expression is an important step in tumor progression as miRNAs can act as tumor suppressors or oncogenes and may affect cell sensitivity to chemotherapy. Whereas the oncogenic miR21 has been shown to be overexpressed in gliomas, the expression and function of the tumor-supressor miR200a in GBMs remains unknown. In this study, we show that miR21 is upregulated in grade IV (GBMs) vs. grade II-III (LGs) gliomas, confirming that miR21 expression level is correlated with tumor grade, and that it may be considered as a marker of tumor progression. Conversely, miR200a is demonstrated for the first time to be downregulated in GBMs compared with LGs, and overexpression of miR200a in GBM cells is shown to promote TMZ-sensitivity. Interestingly, miR200a but not miR21 expression level is significantly higher in TMZ-responsive vs. -unresponsive tumoral glial cells in primary culture. Furthermore, miR200a appears negatively correlated with the expression of the DNA repair enzyme O (6)-methylguanine methyltransferase (MGMT), and the inhibition of MGMT activity results in an increase of miR200a expression in GBM cells. Taken together, these data strongly suggest that miR200a is likely to act as a crucial antitumoral factor regarding glioma progression. Interplay between miR200a and MGMT should be considered as potential mechanism involved in therapeutic response.

Antiangiogenic agents that target the vascular endothelial growth factor (VEGF) pathway have been successfully developed and approved in the vast majority of cancers. As a consequence, an increasing use of antiangiogenic agents has been observed, leading to cost issues and reassessment of their benefit. However, activity on tumor response, and survival benefit of these agents, varies mostly among tumor types and with agents tested. Bevacizumab, a monoclonal antibody against VEGF, was the first antiangiogenic agent that has demonstrated a benefit on progression-free survival (PFS) with or without impact on survival, in patients with advanced and metastatic cancer.1 Glioblastoma multiforme (GBM) is a devastating disease, characterized by a highly angiogenic and invasive phenotype, suggesting a potential role for antiangiogenic strategies. Preclinical data as well as high levels of intratumoral VEGF expression have supported the evaluation of agents that target the VEGF pathway.2 Among them, bevacizumab has been recently approved by the FDA for patients with recurrent glioblastoma, based on a high response rate (RR) with prolonged PFS compared with historical controls3 and is under investigation in the first-line setting.4 Biomarkers able to predict response to antiangiogenic agents and particularly to bevacizumab are an unmet medical need for patients with cancer. The ideal biomarker should be easy to measure on multiple points upon treatment and standardized in their analysis.5 Baseline levels and/or variation of numerous intratumoral or circulating candidate prebiomarkers have been explored. However, to date their predictive significance has been generally weak and rarely confirmed among studies or compared with a cytotoxic treated population. In situ prebiomarkers such as VEGF, VEGF receptor (VEGFR) 2, and carbonic anhydrase 9, as well as plasma prebiomarkers such as VEGF, VEGFR1, intercellular adhesion molecule 1, and interleukin (IL)-6 and -8, have been reported to predict bevacizumab benefit, but this predictive value is generally weak and restricted to one end point (response, PFS, or overall survival [OS]).6 With other antiangiogenic agents such as cediranib in GBM and vandetanib in non–small-cell lung carcinoma, various prebiomarkers, including VEGF, VEGFR2, placenta growth factor (PlGF), basic fibroblast growth factor (bFGF), and matrix metalloproteinase (MMP) 2, present transition variations that have been related to either progression or survival.7,8 Given the remarkable but inconsistent activity of bevacizumab in GBM, we explored the value of selected plasma prebiomarkers to predict response and survival in patients treated with bevacizumab for recurrent high-grade glioma (HGG).

OBJECTIVE To evaluate the effect of CRH administration on plasma AVP and ANF concentration in patients with Cushing's disease and healthy subjects. SUBJECTS Fifteen patients with Cushing's disease and 15 sex- and age-matched healthy subjects entered the study. STUDY DESIGN All subjects were randomly given i.v. 100 μg hCRH and placebo (NaCl 0.9%) on two non consecutive days. Blood samples for plasma AVP and ANF assay were taken before and every 15 min for 2 hr after CRH or placebo. Five out of the 15 patients with Cushing's disease underwent a repeat CRH test after surgical cure of the disease. RESULTS At baseline evaluation, plasma ANF concentrations were significantly higher in patients with Cushing's disease compared to healthy subjects (15.0 ± 0.8 vs 10.8 ± 0.6 pmol/l, P

Peptidylglycine α-amidating monooxygenase (PAM; EC 1.14.17.3) catalyzes the COOH-terminal α-amidation of peptidylglycine substrates, yielding amidated products. Growing evidence suggests that the metabolism of PAM messenger RNAs (mRNAs) can be regulated within the cytoplasm. To understand the mechanisms controlling the metabolism of PAM mRNAs, we sought to identify cis elements of the 3′-untranslated region (3′-UTR) of PAM mRNA that are recognized by cytoplasmic factors. From gel retardation assays, one sequence element is shown to form a specific RNA-protein complex. The protein-binding site of the complex was determined by ribonuclease T1 mapping, by blocking the putative binding site with antisense oligonucleotide, and by competition assays. Using 3′-end-labeled RNA in gel shift and UV cross-linking analyses, we detected in the 3′-UTR a novel 20-nucleotide cis element that interacted with a widely distributed cellular cytosolic protease-sensitive factor(s) to form a 60-kDa PAM mRNA-binding protein complex. The binding activity was redox sensitive. Tissue distribution of the protein in the rat showed a marked tissue-specific expression, with ovary, testis, lung, heart septum, anterior pituitary and hypothalamus containing large amounts compared with liver, ventricle, atrium, and neurointermediate lobe. No binding activity was detectable in pancreas, intestine, or kidney extracts. Northwestern blot analysis of AtT-20 (mouse corticotrope tumor cell line) cytoplasmic extracts revealed a protein of 46 kDa. Thus, we have identified a widely distributed cellular protein that binds to a conserved domain within the 3′-UTR of PAM mRNA from many animal species. Although these data suggest that cis element-binding activity could be a cytoplasmic regulator of PAM mRNA metabolism, the functional consequences of this binding remain to be determined.

Purpose: To study the role of the adrenomedullin system [adrenomedullin and its receptors (AMR), CLR, RAMP2, and RAMP3] in prostate cancer androgen-independent growth. Experimental Design: Androgen-dependent and -independent prostate cancer models were used to investigate the role and mechanisms of adrenomedullin in prostate cancer hormone-independent growth and tumor-associated angiogenesis and lymphangiogenesis. Results: Adrenomedullin and AMR were immunohistochemically localized in the carcinomatous epithelial compartment of prostate cancer specimens of high grade (Gleason score >7), suggesting a role of the adrenomedullin system in prostate cancer growth. We used the androgen-independent Du145 cells, for which we demonstrate that adrenomedullin stimulated cell proliferation in vitro through the cAMP/CRAF/MEK/ERK pathway. The proliferation of Du145 and PC3 cells is decreased by anti-adrenomedullin antibody (αAM), supporting the fact that adrenomedullin may function as a potent autocrine/paracrine growth factor for prostate cancer androgen-independent cells. In vivo, αAM therapy inhibits the growth of Du145 androgen-independent xenografts and interestingly of LNCaP androgen-dependent xenografts only in castrated animals, suggesting strongly that adrenomedullin might play an important role in tumor regrowth following androgen ablation. Histologic examination of αAM-treated tumors showed evidence of disruption of tumor vascularity, with depletion of vascular as well as lymphatic endothelial cells and pericytes, and increased lymphatic endothelial cell apoptosis. Importantly, αAM potently blocks tumor-associated lymphangiogenesis, but does not affect established vasculature and lymphatic vessels in normal adult mice. Conclusions: We conclude that expression of adrenomedullin upon androgen ablation in prostate cancer plays an important role in hormone-independent tumor growth and in neovascularization by supplying/amplifying signals essential for pathologic neoangiogenesis and lymphangiogenesis. Clin Cancer Res; 19(22); 6138–50. ©2013 AACR.

BACKGROUND: Higher vasopressin (AVP) levels have been found in the inferior petrosal sinus ipsilateral to the ACTH-secreting adenoma than in the contralateral one, suggesting a potential pathogenetic role of AVP in Cushing's disease. DESIGN: In order to investigate AVP release, plasma ACTH and AVP concentrations were assayed in the inferior petrosal sinuses and in the peripheral blood before and after CRH stimulation. PATIENTS: Twenty patients with Cushing's disease and 12 with other pituitary diseases were subjected to simultaneous and bilateral inferior petrosal sinus sampling for diagnostic purposes. Ten healthy sex and age-matched subjects served as control for peripheral AVP values. MEASUREMENTS: Plasma ACTH concentrations were measured by RIA using commercial kits. Plasma AVP concentrations were assayed by RIA in acetone extracts of 1-2 ml plasma. RESULTS: Plasma AVP levels in the inferior petrosal sinuses were significantly higher in Cushing's disease than in patients with other pituitary diseases (P < 0.05) and in both groups AVP levels were higher in the inferior petrosal sinuses than in the peripheral blood (P < 0.01). In Cushing's disease, ACTH, but not AVP levels, were higher in the inferior petrosal sinus ipsilateral to the adenoma than in the contralateral one (P < 0.01). Seven patients showed a significant ACTH and AVP increase (greater than 50% of baseline) after CRH stimulation in the inferior petrosal sinus ipsilateral to the adenoma. Conversely, no change was found in AVP levels in the remaining 13 patients. When AVP values were analyzed in relation to surgical cure, higher inferior petrosal sinus levels (P < 0.05) were found in 6 patients with poor outcome: 4 of these patients had significantly decreased plasma AVP concentrations (by 32-43% of baseline) after CRH bolus. Peripheral AVP levels were similar in healthy subjects and patients with Cushing's disease whereas they were significantly reduced in patients with other pituitary diseases (P < 0.002). CONCLUSIONS: The results of this study show that patients with Cushing's disease and poor surgical outcome had the highest AVP levels in our series. CRH administration caused different effects on AVP levels: it increased them in 35% of patients whereas there was no response in the remaining patients. On the basis of these findings, it is hypothesized that AVP might be involved in the persistence of ACTH hypersecretion in a subset of patients poorly responsive to surgery.

During the postnatal period from day 2 to day 10 of life, basal and stress-induced adrenocorticotropic hormone (ACTH) and corticosterone releases are low as compared with adults. This period has been called the ‘stress-hyporesponsive period’, and its mechanisms are yet undetermined. In this study, we have tested the effects of substances excitatory to neuronal activity on the hypothalamic-pituitary-adrenal (HPA) axis. In 7-day-old rats, administration of the excitatory amino acid (EAA) agonists N-methyl-D-aspartic acid (NMA), quisqualic acid, and kainic acid (KA) induced a large increase in plasma ACTH and corticosterone concentrations. All three EAA induced a rapid and potent stimulation of ACTH release within 30 min, the effect on corticosterone secretion being weaker. KA was the more potent EAA, followed by NMA and quisqualic acid. The effect of NMA on the HPA axis was inhibited by pretreatment with a competitive antagonist to N-methyl-D-aspar-tic acid receptors, D, L-2-amino-5-phosphonovaleric acid. We next sought to determine which level of the HPA axis was affected by EAA administration. Several EAA (glutamic acid, N-methyl-D-aspartic acid, and KA from 10-5 to 10-2M) had no stimulating action on ACTH release from 7-day-old anterior pituitary glands incubated in vitro. In vivo, the stimulating effect of NMA and KA on in vivo ACTH release was blocked after passive immunization with an anti-corticotropin-releasing hormone antiserum, but not after injection of an anti-arginine vasopressin antiserum. These results suggest that during stress-hyporesponsive period, the HPA axis can be stimulated by excitatory substances acting at the hypothalamic or suprahypothalamic level.

Plasma ACTH, beta-endorphin and alpha-melanocyte-stimulating hormone levels were evaluated in the inferior petrosal sinuses and in the periphery of 22 patients affected by Cushing's disease, 11 patients with other pituitary diseases subjected to simultaneous and bilateral inferior petrosal sinus sampling and in the peripheral blood of 15 normal subjects. In patients with Cushing's disease ACTH, beta-endorphin and alpha-melanocyte-stimulating hormone levels in the inferior petrosal sinus ipsilateral to the adenoma were significantly higher than in the periphery and in the contralateral inferior petrosal sinus (p < 0.01, p < 0.01 and p < 0.05, respectively). In patients with other pituitary diseases only ACTH and beta-endorphin, but not alpha-melanocyte-stimulating hormone levels in both inferior petrosal sinuses were significantly higher than in the periphery (p < 0.01). Furthermore, no difference was found in the peripheral blood among patients with Cushing's disease, patients with other pituitary diseases and normal subjects for ACTH and beta-endorphin level. By contrast, in patients with Cushing's disease peripheral alpha-melanocyte-stimulating hormone levels were significantly higher than in patients with other pituitary diseases and in normal subjects (p < 0.05). In conclusion, the results of the present study suggest that only in patients with Cushing's disease, but not in patients with other pituitary diseases, alpha-melanocyte-stimulating hormone is released by adenomatous pituitary corticotrophs together with ACTH and beta-endorphin.

Clinical and experimental studies suggest that angiogenesis is a prerequisite for solid tumour growth. Glioblastoma (GBM) and pilocytic astrocytoma (PA), both angiogenic tumours display strong contrast enhancement associated with peripheral oedema in GBM but not in PA indicating differences in vascular permeability in these two types of gliomas. Here we show that expression of adrenomedullin (AM) mRNA is induced in GBM whereas is barely detectable in PA. In situ analysis of tumour specimens undergoing neovascularisation shows that the production of AM is specifically induced in a subset of GBM cells distinguished by their immediate proximity to necrotic foci (presumably hypoxic regions), suggesting a hypoxic induction of AM expression in GBM. Vascular endothelial growth factor (VEGF) mRNA levels are increased in GBM and moderate in PA. Immunohistochemical study showed that cytoplasmic AM, VEGF and HIF-1α nuclear immunoreactivity were recorded in GBM located near large necrotic areas whereas they were not expressed by PA tumour cells. Interestingly, double fluorescence immunostaining demonstrated that 85% of AM immunoreactivity colocalised with VEGF. AM transduces its effects through calcitonin receptor-like receptor/receptor activity modifying protein-2 and -3 (CLR/RAMP2 and CLR/RAMP3). Real-time quantitative RT-PCR showed expression of RAMP2, RAMP3 and CLR in PA and GBM, suggesting that AM may function as an autocrine/paracrine growth factor for GBM cells. These observations strongly support the concept that tumour angiogenesis is regulated by paracrine mechanisms and identify beside VEGF, AM as a potential tumour angiogenesis factor in vivo which constitutes a potential interesting molecular target in GBM treatment.

Preproenkephalin metabolism, in the rat, was studied in primary striatal neurons maintained in a chemically defined medium. Acute treatment (30 min) with forskolin (10 −5 M) or phorbol 12 myristate 13 acetate (10 −7 M) resulted, respectively, in a two- and seven-fold increase in methionine-enkephalin secretion. Chronic treatment with forskolin or phorbol 12 myristate 13 acetate (24 h) induced a 100% increase in methionine-enkephalin content (forskolin) and on the other hand a 50% decrease in methionine-enkephalin (phorbol 12 myristate 13 acetate). Both treatments increased preproenkephalin mRNA levels in a time-dependent manner, this augmentation being observable after 180 min by Northern blot analysis and in situ hybridization. These data indicate that under chronic stimulation, with either forskolin or phorbol 12 myristate 13 acetate, proenkephalin turnover is accelerated. However, after stimulation with phorbol 12 myristate 13 acetate, the more potent methionine-enkephalin secretagogue, increased peptide synthesis is not sufficient to replenish methionine-enkephalin intracellular stores. Preproenkephalin gene transcription was analysed by introducing the preproenkephalin gene promoter fused to the bacterial acetyl chloramphenicol transferase reporter gene into primary neurons. Chronic stimulation (48 h) by forskolin (10 −5 M) or phorbol 12 myristate 13 acetate (10 −7 M) of striatal neurons transfected with this fusion gene increased chloramphenicol acetyltransferase activity six-fold and the two effects were additive. These data suggest that the cyclic AMP and the protein kinase C pathways directly activate preproenkephalin gene transcription.

Neuroendocrine (NE) differentiation in prostate cancer (CaP) has been reported to be an early marker associated with the development of androgen independence. The mechanisms by which CaP acquires NE properties are poorly understood. In this study, a putative role of adrenomedullin (AM) in the NE differentiation was investigated. The expression of AM and AM receptors (calcitonin receptor-like receptor (CRLR)/receptor activity modifying protein-2 and -3 (RAMP2 and RAMP3) was evaluated after experimental manipulation of androgen status. Levels of AM mRNA and immunoreactive AM (ir-AM) increased four- to sevenfold in androgen-sensitive LNCaP cells after androgen withdrawal in vitro and in LNCaP xenografts in animals after castration. Treatment of LNCaP cells with androgen analogue (dihydrotestosterone; 10(-9) M) prevented the increase in AM mRNA and ir-AM levels. Interestingly, the expression of CRLR, RAMP2 and RAMP3 is not regulated by androgen status. We demonstrate that in the presence of serum, AM is able to induce an NE phenotype in LNCaP cells via CRLR/RAMP2 and RAMP3, which includes extension of neuritic processes and expression of the neuron-specific enolase (NSE), producing cGMP in a dose-dependent manner, which is mediated by a pertussis toxin-sensitive GTP-binding protein. 8-Bromo-cGMP mimicked the effects of AM on cell differentiation. We demonstrate that AM induces a G-kinase Ialpha translocation to the nucleus. The protein kinase G inhibitor KT-5823 inhibited the neurite outgrowth induced by both AM and 8-bromo-cGMP. In noncastrated animals, administration of AM enhanced expression of NSE and chromogranin A in LNCaP xenografts with a significant increase of NSE levels in serum and no changes in tumor growth. In castrated animals, intraperitoneal injection of AM resulted in a 240+/-18% (P

Peptidyl-glycine alpha-amidating monooxygenase (PAM) is a posttranslational processing enzyme which catalyzes the formation of biologically active alpha-amidated peptides. The two major neuropeptides involved in the regulation of ACTH secretion [CRF and arginine vasopressin (AVP)], synthesized in the parvocellular part of the hypothalamic paraventricular nucleus (PVN), are amidated, and their synthesis and/or release is negatively regulated by glucocorticoids. In this study, using in situ hybridization, we have shown that PAM mRNA is abundantly expressed in the hypothalamic paraventricular and supraoptic nucleus. Surgical adrenalectomy (ADX) induced increases in PAM, CRF, and AVP mRNA in the parvocellular part of the PVN, while corticosterone treatment normalized these values. PAM and AVP gene expression were not changed in the magnocellular part of the PVN or in the supraoptic nucleus. These observations suggest that in addition to stimulation of CRF and AVP synthesis, ADX induces an increase in PAM synthesis in the PVN and, thus, support the hypothesis of increased secretion of both CRF and AVP after ADX.

The hypothalamus of both adult and fetal rats contains a population of cells which can exhibit some features of serotoninergic (5-HT) neurons under certain circumstances. However, their neuronal serotoninergic nature is still controversial. In fact the presence of tryptophan hydroxylase activity has not yet been clearly established. This study attempted to verify whether [3H]5-HT can be synthesized from [3H]tryptophan ([3H]TRP) in hypothalamic cell cultures from 16-day-old fetuses. Data showed that [3H]5-HT was synthesized from [3H]TRP and the amounts of [3H]5-HT increased linearly as a function of time for 60 min. Pargyline markedly increased the quantities of [3H]5-HT and decreased those of [3H]5-hydroxyindole acetic acid, [3H]5-HT synthesis was inhibited by p-chlorophenylalanine, while α-methyl-p-tyrosine had no effect. The present biochemical study shows the presence of an intrinsic 5-HT neuronal system in the hypothalamus of the fetal rat.

Objective: Adrenomedullin (AM), a potent vasodilatator and antioxidative peptide, was shown recently to be expressed by adipose tissue. The aim of our study was to investigate the precise localization of AM within human adipose tissue, and to examine AM regulation in obesity. Design: Subcutaneous (SC) and omental (OM) adipose tissues from 9 lean and 13 obese women were profiled for AM expression changes. Preadipocytes from human adipose tissue were isolated and differentiated under defined adipogenic conditions. Methods: AM expression was analyzed by immunohistochemistry, in situ hybridization and quantitative RT-PCR. Results: A strong AM expression was observed in vessel walls, stromal cell clusters and isolated stromal cells, some of them being CD 68 positive, whereas mature adipocytes were not labeled. Calcitonin receptor-like receptor and receptor activity-modifying proteins (RAMP) 2 and RAMP 3 were expressed in vessel walls. In vitro, preadipocytes of early differentiation stages spontaneously secreted AM. No difference in AM localization was found between SC and OM adipose tissue. AM levels in SC tissue did not differ between lean and obese subjects. By contrast, AM levels in OM tissue were significantly higher in obese as compared with lean women. Moreover, we found a positive relationship between OM AM and tumor necrosis factor α mRNA levels and AM-immunoreactive area in OM tissue followed the features of the metabolic syndrome. Conclusion: Stromal cells from human adipose tissue, including macrophages, produce AM. Its synthesis increased in the OM territory during obesity and paralleled the features of the metabolic syndrome. Therefore, AM should be considered as a new member of the adipokine family.

Recently, we demonstrated that U87 glioblastoma xenograft tumors treated with anti-adrenomedullin (AM) antibody were less vascularized than control tumors, suggesting that AM might be involved in neovascularization and/or vessel stabilization. Angiogenesis, the sprouting of new capillaries from preexisting blood vessels, is a multistep process that involves migration and proliferation of endothelial cells, remodeling of the extracellular matrix and functional maturation of the newly assembled vessels. In our study, we analyzed the role of AM on human umbilical vein endothelial cell (HUVEC) phenotype related to different stages of angiogenesis. Here we report evidence that AM promoted HUVEC migration and invasion in a dose-dependent manner. The action of AM is specific and is mediated by the calcitonin receptor-like receptor/receptor activity-modifying protein-2 and -3 (CRLR/RAMP2; CRLR/RAMP3) receptors. Furthermore, AM was able to induce HUVEC differentiation into cord-like structures on Matrigel. Suboptimal concentrations of vascular endothelial growth factor (VEGF) and AM acted synergistically to induce angiogenic-related effects on endothelial cells in vitro. Blocking antibodies to VEGF did not significantly inhibit AM-induced capillary tube formation by human endothelial cells, indicating that AM does not function indirectly through upregulation of VEGF. These findings suggest that the proangiogenic action of AM on cultured endothelial cells via CRLR/RAMP2 and CRLR/RAMP3 receptors may translate in vivo into enhanced neovascularization and therefore identify AM and its receptors acting as potential new targets for antiangiogenic therapies. © 2003 Wiley-Liss, Inc.

The sheep is a valuable model to study growth hormone (GH) neuroregulation since its GH secretion pattern is close to that in humans and an integrated physiological approach is possible in this species. Somatostatin receptor subtype 5 (sst5) appears to be important in GH regulation but the ovine sst5 gene (osst5) has not yet been cloned. We report here the cloning of sst5 in that species. We screened a cDNA sheep library and isolated a 1.24 kb cDNA, which includes the whole coding region of osst5. The predicted protein consists of 367 amino acids exhibiting a putative seven transmembrane domain topology typical of G protein-coupled receptors. Nucleotide sequence comparisons with that of other species sst5 showed that osst5 displays 83.8, 81 and 79.7% homology with human, rat, and mice sst5, respectively. Southern blot analysis of ovine cortex DNA demonstrated that osst5 is encoded by a single gene. Osst5 transiently expressed in Chinese Hamster ovary (CHO) cells exhibit a high affinity for somatostatin-14. Reverse transcriptase-polymerase chain reaction (RT-PCR) studies demonstrated that osst5 mRNAs are present in pituitary, cortex, hypothalamus, hippocampus, colon and adrenal gland. The cloning of osst5 should provide a useful tool to study the mechanisms through which somatostatin inhibits hormone secretion in the sheep.

Presently, there is no effective treatment for glioblastoma, the most malignant and common brain tumor. Growth factors are potential targets for therapeutic strategies because they are essential for tumor growth and progression. Peptidylglycine alpha-amidating monooxygenase is the enzyme producing alpha-amidated bioactive peptides from their inactive glycine-extended precursors. The high expression of peptidylglycine alpha-amidating monooxygenase mRNA in glioblastoma and glioma cell lines points to the involvement of alpha-amidated peptides in tumorigenic growth processes in the brain. After screening of amidated peptides, it was found that human glioblastoma cell lines express high levels of adrenomedullin (AM) mRNA, and that immunoreactive AM is released into the culture medium. AM is a multifunctional regulatory peptide with mitogenic and angiogenic capabilities among others. Real-time quantitative reverse transcriptase-polymerase chain reaction analysis showed that AM mRNA was correlated to the tumor type and grade, with high expression in all glioblastomas analyzed, whereas a low expression was found in anaplastic astrocytomas and barely detectable levels in low-grade astrocytomas and oligodendrogliomas. In the present study we also demonstrate the presence of mRNA encoding the putative AM receptors, calcitonin receptor-like receptor/receptor activity-modifying protein-2 and -3 (CRLR/RAMP2; CRLR/RAMP3) in both glioma tissues and glioblastoma cell lines and further show that exogenously added AM can stimulate the growth of these glioblastoma cells in vitro. These findings suggest that AM may function as an autocrine growth factor for glioblastoma cells. One way to test the autocrine hypothesis is to interrupt the function of the endogenously produced AM. Herein, we demonstrate that a polyclonal antibody specific to AM, blocks the binding of the hormone to its cellular receptors and decreases by 33% (P < 0.001) the growth of U87 glioblastoma cells in vitro. Intratumoral administration of the anti-AM antibody resulted in a 70% (P < 0.001) reduction in subcutaneous U87 xenograft weight 21 days after treatment. Furthermore, the density of vessels was decreased in the antibody-treated tumors. These findings support that AM may function as a potent autocrine/paracrine growth factor for human glioblastomas and demonstrate that inhibition of the action of AM (produced by tumor cells) may suppress tumor growth in vivo.

2074 Background: We have previously showed that a high MMP2, and to a lesser extend a low MMP9 plasma levels were associated to a high response rate, a prolonged PFS and OS in recurrent GB treated ...

International audience; Peptidylglycine alpha-amidating monooxygenase (PAM), which catalazyes the two-step formation of bioactive alpha-amidated peptides from their glycine-extended precursors, has been found in H9c2 myoblasts. The expression of PAM has been evaluated in H9c2 cells. Northern blot analysis and amplification of fragments derived from rat PAM by the reverse transcription/polymerase chain reaction method has demonstrated the presence of rPAM-1, -2, -3, -3a and -3b mRNA transcripts. These forms of PAM mRNA may be generated by alternative splicing. PAM mRNA levels are increased to 160 +/- 12% of control values by treatment with dexamethasone but are unchanged during triiodothyronine incubation of the cells. PAM activity is very low, which is not comparable to the high levels found in adult atrium tissue. Western blot analysis has demonstrated 86-, 76-, and 46-kDa PAM proteins in the particulate fraction. The soluble fraction contains major PAM proteins of 110, 86, and 46 kDa. In situ hybridization studies with 35S-labeled full length RNA antisense transcripts of rat PAM-1 cDNA have localized autoradiographic grains around the nucleus. Our data clearly demonstrate PAM expression in H9c2 rat heart cells, suggesting the ability of these cardiac cells to make bioactive alpha-amidated hormones and/or neuropeptides.

Peptidylglycine alpha-amidating monooxygenase (PAM; EC 1.14.17.3) is a bifunctional protein containing two enzymes that act sequentially to catalyse the alpha-amidation of neuroendocrine peptides. Previous studies have demonstrated that alpha-adrenergic stimulation results in an increase in intracellular volume and protein content of cultured neonatal rat myocardial cells. The present study examined the regulated expression of PAM during alpha-adrenergic stimulation. Alpha1-adrenergic stimulation activates the expression and release of PAM from myocytes. Following phenylephrine treatment, myocardial cells displayed a several fold increase in PAM activity, and a 2-4-fold increase in the steady state levels of PAM mRNA. This effect of alpha-adrenergic stimulation was dependent on the concentration and duration of exposure to the agonist, and displayed alpha1-adrenergic receptor specificity. The transcription rate experiments indicated that these alpha-adrenergic effects were not due to increased PAM gene activity, suggesting that a post-transcriptional mechanism was involved. The most common mechanism of post-transcriptional regulation affects cytoplasmic mRNA stability. Cardiomyocytes cultures from atria and ventricles in the presence of 5,6 dichloro-1-beta ribofuranosyl benzamidazole (DRB) showed that phenylephrine treatment increased the half-life of PAM mRNA from 13 +/- 1 to 21 +/- 1 h in atrial cells and from 8 +/- 1 to 12 +/- 1 h in ventricle cells. Analysis of nuclear RNA with probes specific for PAM intron sequences shows that increased PAM expression after phenylephrine treatment was not due to intranuclear stabilisation of the primary transcript. Protein kinase C inhibitors H7 and GF109203x, completely blocked the phenylephrine stimulated PAM expression. These results suggest that alpha-adrenergic agonist induces PAM mRNA levels by increasing its stability in the cytoplasm. They indicate that PAM gene expression augments through a H7 and GF109203x sensitive pathway, involving the activation of protein kinase C.

In the present study, high levels of peptidylglycine α-amidating monooxygenase (PAM), which catalyzes the two-step formation of bioactive α-amidated peptides from their glycine-extended precursors, have been found in the uterus. Expression of PAM was evaluated in the uterus of intact cycling adult female rats and after experimental manipulation of the estrogen status of the rats. During the estrous cycle, PAM mRNA levels exhibited striking changes inversely related to the physiological variations of plasma estrogen levels. The levels of PAM transcripts changed markedly during the estrous cycle, reaching the highest levels at metestrus. There was a 15-fold increase in the abundance of PAM mRNA between metestrus and proestrus. Chronic treatment of ovariectomized rats with 17β-estradiol decreased PAM mRNA levels to values comparable with those found in intact rats at proestrus. Progesterone was without effect on PAM mRNA levels, indicating that the effect was specific for estradiol. In situ hybridization studies were conducted to determine the tissue disposition and cell types expressing PAM. High levels of PAM mRNA were localized in the endometrium at the level of luminal and glandular cells. A weak signal was observed in stromal cells, and the myometrium cells were negative. 17β-Estradiol treatment induced an overall decrease of the hybridization signal, as compared with ovariectomized rats. These results demonstrate the presence of high levels of PAM in the uterus and indicate that estrogens are involved in regulating the expression of the enzyme in this tissue. However, the present study provides no information regarding whether this regulation takes place at the level of transcription or influences mRNA stability.

Peptidylglycine alpha-amidating monooxygenase (PAM; EC 1.14.17.3) is a bifunctional protein containing two enzymes that act sequentially to catalyze the conversion of glycine-extended peptides into COOH-terminal amidated peptides. We have previously shown that PAM messenger RNA (mRNA) levels in the anterior pituitary of intact cycling adult female rats showed changes inversely related to the physiological variations of plasma estrogen levels during the estrous cycle. Chronic treatment of ovariectomized (OVX) rats with 17beta-estradiol was accompanied by a 4.5 +/- 0.5-fold decrease in total PAM mRNA and a 2-fold decrease in PAM activity in the anterior pituitary gland. To investigate the cellular site at which 17beta-estradiol acts to affect the PAM mRNA, we made parallel measurements of the relative levels of PAM mRNA and nuclear precursor RNA and the relative rate of gene transcription after treatments designed to alter the estrogen status. The transcription rate experiments indicated that these 17beta-estradiol effects were not due to reduced PAM gene activity, suggesting that a posttranscriptional mechanism was involved. The most common mechanism of posttranscriptional regulation affects cytoplasmic mRNA stability. Primary rat pituitary cell cultures from OVX and OVX-17beta-estradiol-treated rats in the presence of actinomycin D showed that 17beta-estradiol treatment decreased the half-life of PAM mRNA from 15-16 h to 8-9 h. There was no effect of 17beta-estradiol on PAM mRNA poly(A) tail length or site of polyadenylation. However, in this study the down-regulation of PAM was identified as a nuclear event. Analysis of nuclear RNA with probes specific for PAM intron sequences shows that decreased PAM expression after 17beta-estradiol treatment was largely due to intranuclear destabilization of the primary transcript. The levels of nuclear precursor RNA were decreased roughly 5- to 6-fold in OVX + 17beta-estradiol compared with OVX rats. The decrease in PAM mRNA is blocked by cycloheximide, indicating that its requires new protein synthesis. Mechanisms that would generate such an effect include altered stability of unprocessed message in the nucleus. The proportional changes observed in the nuclear precursor and mRNA levels suggest that the site of control is at the level of stability of the nuclear precursor RNA for PAM mRNA.

The pituitary is a rich source of peptidylglycine alpha-amidating monooxygenase (PAM). This bifunctional protein contains peptidylglycine alpha-hydroxylating monooxygenase (PHM) and peptidyl-alpha-hydroxyglycine alpha-amidating lyase catalytic domains necessary for the two-step formation of alpha-amidated peptides from their COOH-terminal glycine extended precursors. Expression of PAM was evaluated in the anterior pituitary of intact cycling adult female rat and after experimental manipulation of estrogen status. PAM messenger RNA (mRNA) levels showed changes inversely related to the physiological variations of plasma estrogen levels during the estrous cycle. Chronic treatment of ovariectomized (OVX) rats with 17 beta-estradiol decreased PAM mRNA levels to values comparable with those found in intact rats at proestrus. In situ hybridization of anterior pituitary sections using 35S-labeled full length RNA antisense transcripts of rat PAM-1 complementary DNA showed that 17 beta-estradiol treatment induced an overall decrease of the hybridization signal, as compared with OVX rats. Progesterone treatment did not change PAM mRNA levels both in OVX or OVX + E2 rats. Based on Northern blot analysis and amplification of fragments derived from rat PAM-1 by RT-PCR, it was found that estrogen status does not affect the distribution of PAM mRNA among its various alternatively spliced forms. In OVX 17 beta-estradiol treated rats, the specific activity of PAM in the anterior pituitary decreased in both soluble and particulate fractions compared with OVX animals. Western blot analysis demonstrated a 105-kDa PAM protein in particulate fractions prepared from OVX and OVX-17 beta-estradiol treated animals. The soluble fraction from OVX animals contained major PAM proteins of 105, 95, 84, 75, and 45 kDa, and 17 beta-estradiol treatment caused a decrease in the prevalence of these proteins. These results indicate that estrogens are involved, either directly or indirectly, in regulating the expression of PAM in several cell types in the anterior pituitary gland.

2024 Background: Predictive marker of Bev activity is an unmet medical need. We evaluated predictive value of selected circulating prebiomarkers involved in neoangiogenesis and invasion on patient outcome in recurrent HGG treated with Bev. Methods: A set of eleven prebiomakers of interest (VEGF, VEGF-R2, bFGF, SDF1, PlGF, uPA, PAI1, MMP2, MMP7, MMP9, and adrenomedulline) were analyzed in plasma, using ELISA, at baseline from Bev initiation in a prospective cohort of 26 patients (Cohort1). Correlations were validated in a separate retrospective Bev treated cohort (Cohort2; n = 50) and then tested in a cohort of patients treated with cytotoxic agents without Bev (Cohort3; n = 34). Dosages were correlated to OR, PFS, and OS. MMP2 and MMP9 were then analyzed at multiple time points up to progression. Results: In cohort1, high MMP2 baseline level was associated with an OR rate of 83.3% for high levels versus 15.4% for low MMP2 levels (p = 0.001). In multivariate analysis, MMP2 baseline level was correlated with PFS (hazard-ratio (HR), 3.92; 95% confidence-interval (CI):1.46-10.52; p = 0.007) and OS (HR, 4.62; 95%CI 1.58-13.53; p = 0.005), as MMP9 (p = 0.016 for PFS and p = 0.025 for OS). Similar results were found in cohort2 for MMP2, (MMP2: p

Peptidylglycine alpha-amidating monooxygenase (PAM; EC 1.14.17.3) is a multifunctional protein containing two enzymes that act sequentially to catalyze the alpha-amidation of neuroendocrine peptides. The regulatory mechanism(s) involved in the tissue-specific induction of PAM messenger RNA (mRNA) by thyroid status have been investigated in rat anterior pituitary gland. In this tissue, cellular PAM mRNA increases in response to hypothyroidism (4- to 7-fold above basal levels). To gain further insight into this pretranslational control, nuclear in vitro run-on transcription assays were performed. Using PAM complementary DNAs and intronic probe, we showed that the transcriptional rate of rat pituitary PAM gene in isolated nuclei was not altered by thyroid status. Primary rat pituitary cells cultures from hypo- and euthyroid rats in the presence of actinomycin D showed that hypothyroidism increased the half-life of PAM mRNA from 9-10 h to 15-17 h. Taken together, these data suggest that hypothyroidism induces PAM mRNA levels by increasing its stability in the cytoplasm.

The effect of corticotropin (ACTH)-releasing hormone (CRH) administration on alpha-melanocyte-stimulating hormone (alpha-MSH), ACTH and beta-endorphin (beta-EPH) was evaluated in the inferior petrosal sinuses and in the periphery of 30 patients affected with Cushing's disease subjected to simultaneous and bilateral inferior petrosal sinus sampling for diagnostic purposes. Baseline PRL levels, sensitivity to dexamethasone and surgery outcome were compared to alpha-MSH response. CRH bolus did not modify alpha-MSH concentrations either in the inferior petrosal sinuses or in the periphery in the 30 patients considered as a whole. In 7 of 30 patients, however, a greater than 50% increase over baseline alpha-MSH levels (from 50 to 115.5%) was recorded in the inferior petrosal sinus ipsilateral to the adenoma (from 42.9 +/- 1.7 to 76.4 +/- 4.6 ng/l; p < 0.001), whereas no change was found in the contralateral inferior petrosal sinus or in the periphery. Conversely, as expected, ACTH and beta-ELI significantly increased in all the patients after CRH both in the inferior petrosal sinuses and in the periphery (particularly in the inferior petrosal sinus ipsilateral to the adenoma). No difference in sensitivity to dexamethasone (urinary cortisol percent decrease: 66.4 +/- 4.9 vs. 67.8 +/- 3.4) and surgery outcome (chi 2 test: p = 0.7) was found between patients with alpha-MSH response to CRH and patients without such a response. By contrast, baseline PRL levels, although being normal in both groups, were significantly higher in patients with alpha-MSH response to CRH (18.1 +/- 1.6 vs. 10.1 +/- 0.7 micrograms/l; p < 0.001). In conclusion, the results of the present study suggest that in a subset of patients with Cushing's disease (23.3% of our series) alpha-MSH may be released after the administration of CRH together with ACTH and beta-EPH by adenomatous corticotrophs. In this subset of patients, PRL levels may be in the upper normal range.

Background Predictive marker of bevacizumab activity is an unmet medical need, while activity of this anti-VEGF Mab is reported to be heterogeneous, particularly in glioblastoma. Objective To identify circulating biomarker that predicts response to bevacizumab and outcome in recurrent high grade glioma (HGG). Methods Eleven angiogenic makers were analyzed, using ELISA, at baseline and one month apart from bevacizumab initiation in a first cohort of 26 HGG patients of our institution (cohort 1); Plasma marker dosages were correlated to objective response (RANO criterias), Progression-free survival (PFS), and overall survival (OS). Correlations were validated in a separate cohort of 50 patients (Cohort 2). Markers analyses were performed in two other cohorts treated with cytotoxic agents up front (cohort 3 n = 20) or concomitant to radiotherapy (cohort 4 n = 24). Results In cohort 1, high MMP2 baseline level was associated to a probability of response of 83.3% versus 15.4% in case of low MMP2 level (p = 0.001). By univariate analyses, confirmed by multivariate analysis, MMP2 correlated with PFS (p = 0.007) and OS (p = 0.001), as decrease of plasmatic VEGF level (p = 0.038 for PFS and p = 0.013 for OS) and MMP9 level (PFS p = 0.016, OS p = 0.025). These results were confirmed with a similar magnitude in cohort 2 for MMP2 only (p Conclusions Among patients with recurrent HGG treated with bevacizumab, but apparently not with cytotoxic agent, higher plasma MMP2 levels were associated with objective response, prolonged tumor control and survival. Further studies are needed to validate the predictive value of these/this biomarker(s) both with glioma and other cancers. Disclosure O. Chinot: Roche consultant. All other authors have declared no conflicts of interest.

Aim of the present study was the evaluation of ACTH and beta-endorphin-like-immunoreactivity (beta-ELI) in the inferior petrosal sinuses (IPS's) and in the peripheral blood of patients with Cushing's disease (Group 1), with GH- or PRL-secreting adenomas or nontumoral hyperprolactinemia (Group 2). These patients had undergone selective and bilateral simultaneous IPS sampling for diagnostic purposes or for neurosurgical indications. In the patients of Group 1, ACTH and beta-ELI levels were higher in the IPS ipsilateral than in the contralateral to the adenoma and in the periphery (p < 0.001). In the patients of Group 2 ACTH and beta-ELI levels were higher in the IPS's than in the peripheral blood (p < 0.001) and, in the 9 patients with GH- or PRL-secreting adenomas, they were higher in the IPS ipsilateral than in the contralateral to the adenoma and in the periphery (p < 0.05). A significant correlation exists between ACTH and beta-ELI in the periphery (p < 0.01; r = 0.72), in the IPS ipsilateral (p < 0.05; r = 0.54) and contralateral (p < 0.01; r = 0.66) to the adenoma in Group 1, but not in Group 2. In conclusion, higher beta-ELI levels were detected in the IPS's than in the peripheral blood not only in patients with Cushing's disease but also in those with other pituitary diseases not involving ACTH secretion. The absence of correlation between ACTH and beta-ELI in patients not bearing Cushing's disease suggests that in these conditions corticotrophs release ACTH and beta-endorphin in an independent manner.

The effects of rapid changes of circulating cortisol levels on ACTH secretion and on corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) concentrations into hypophysial portal blood were studied in six adult rams. Pharmacological adrenalectomy was obtained by 3 h metyrapone infusion (100 mg·kg−1·h−1). Blockade of cortisol synthesis induced a tenfold increase of plasma ACTH levels accompanied by a moderate increase of CRF secretion (150% vs preinjection levels) and a large increment of AVP secretion (535% vs preinjection levels). ACTH levels remained high during the 3 h following the end of metyrapone infusion. During the same period, CRF secretion was still elevated (231% vs preinjection levels), while AVP secretion was further stimulated (2,151% vs preinjection levels). Subsequent hydrocortisone infusion (66 μg·kg−1·h−1) for 2 h induced a rapid decrease of both ACTH and AVP secretion, while CRF levels in hypophysial portal blood still remained elevated. These data suggest that changes in ACTH secretion induced by acute modifications of the negative glucocorticoid feedback are, in addition to the well documented direct effect of cortisol on the corticotropes, mainly mediated by variations of hypothalamic AVP secretion.

ACTH and cortisol diurnal variations and responses to two types of stress (insulin-induced hypoglycemia and isolation-restraint stress) and to an acute injection of CRF were determined in intact as well as in actively antiarginine vasopressin (AVP)-immunized rams. All immunized sheep developed antibodies to AVP, displayed diabetes insipidus, and looked healthy in spite of their lower gain weight. Basal secretion and diurnal variations of ACTH and cortisol were unaltered in the group of anti-AVP-immunized animals. In contrast, ACTH and cortisol responses to both types of stress and CRF injection were significantly reduced compared to those in controls. These results suggest that endogenous AVP plays a physiological role in the corticotropic response to stress. However, endogenous AVP does not appear to affect basal secretion and diurnal variations of ACTH and cortisol.

ACTH and cortisol diurnal variations and responses to two types of stress (insulin-induced hypoglycemia and isolation-restraint stress) or to an acute injection of lysine-vasopressin were studied in intact and anti-corticotropin-releasing factor (CRF) actively immunized rams. Immunization was obtained by the injection of synthetic ovine CRF coupled to BSA with carbodiimide. All animals developed antibodies anti-CRF and displayed an alteration of their general condition and a body weight reduction. The mean basal ACTH and cortisol secretion as well as the number and mean amplitude of diurnal pulses of these hormones was significantly reduced in the group of anti-CRF immunized rams. However, the reduction in all three parameters was much more pronounced for cortisol than for ACTH. No ACTH and cortisol response to insulin-induced hypoglycemia and isolation-restraint stress was observed. The stimulating action of lysine-vasopressin on ACTH release was significantly reduced as compared to controls. These results indicate that CRF is a major physiological component of the ovine hypothalamo-hypophysial-adrenal axis and participates in the events that regulate ACTH and cortisol diurnal variations and response to stress.

2059 Background: Identification of circulating markers that predict tumor response or reflect progression is of crucial importance when using antiangiogenic agents. However, to date, no such parameters have been identified particularly for bevacizumab, for which, recently, increasing data have supported a role in patient with recurrent malignant glioma. Methods: Serial serum levels of VEGF, VEGFR2, FGF, SDFα, urokinase plasminogen activator (uPA), plasminogen activator inhibitor type I (PAI-1), and metalloprotesase type 9 (MMP9) were determined in a cohort of 32 patients treated with bevacizumab and irinotecan for recurrent malignant glioma. Samples were collected at the start of treatment and then at 4 weeks intervals until progression. Serum levels were measured using an enzyme-linked immunosorbent assay. Progression was defined by MacDonald's criteria, modified by integrating increase of infiltration as measured on MRI by Flair sequence. All subjects were followed for PFS and OS. Cox model analysis is used for correlation between markers and clinical outcome. Results: This preliminary analysis is restricted to pre-treatment (D0; n = 32), day 30 (D30; n = 27), and at progression time (DP; n = 15). None of the pretreatment serum level (n = 32) significantly affect PFS or OS although uPA and MMP9 tend to influence OS. Decrease of median level of all serum markers except PAI1 and VEGFR2 is observed from D0 to D30 under bevacizumab therapy, but only uPA and FGF variations tend to impact clinical outcome. From D30 to DP, increase of uPA is correlated to PFS (p = 0.028) while the observed increased of FGF and SDFα fail to reach significant correlation to PFS and OS. Conclusions: Increase of uPA serum level appear to be correlated to disease progression for patients with recurrent malignant glioma treated with bevacizumab and may reflect the invasive phenotype of glioma progression. Serum uPA may help in assessing treatment response under bevacizumab and warrant further studies. No significant financial relationships to disclose.

Insulin-induced hypoglycemia (IIH) is a strong stimulator of pituitary ACTH secretion. The mechanisms by which IIH activates the corticotrophs are still controversial. Indeed, in rats the variations of corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) secretion in hypophysial portal blood (HPB) during IIH have been diversely appreciated. This may be due to the stressful conditions required for portal blood collection in rats. We studied the effects of IIH on the secretion of CRF and AVP in HPB and on the release of ACTH and cortisol in peripheral plasma in conscious, unrestrained, castrated rams. After the injection of a low (0.2 IU/kg) or high dose (2 IU/kg) of insulin, ACTH and cortisol levels in peripheral plasma increased in a dose-related manner. After injection of the low dose of insulin, CRF and AVP secretion in HPB were equally stimulated. After injection of the high dose of insulin, CRF secretion was further stimulated, while AVP release was dramatically increased. These results suggest that when the hypoglycemia is moderate, CRF is the main factor triggering ACTH release, and that the increased AVP secretion potentiates the stimulatory effect of CRF. When hypoglycemia is deeper, AVP secretion becomes predominant and may by itself stimulate ACTH release.

Normally glucose accounts for more than 90% of the metabolic fuel of the brain (1). A constant supply and utilization of glucose is essential for normal cerebral metabolism since brain carbohydrate stores are very small. Hypoglycemia as well as diabetes mellitus result in a variety of neuroendocrine alterations probably through changes in the rate of glucose uptake and metabolism in the hypothalamus. At the hypothalamic-pituitary level, two metabolic conditions can be realized: either increased glucose disposal after administration of exogenous glucose, or glucopenia due to hypoglycemia or diabetes. In the latter condition, blood glucose increased, but cannot be utilized in brain cells because of the lack of insulin secretion. Changes in pituitary hormone release under these acute or chronic alterations in blood glucose levels have been well characterized. However, the role of the hypothalamus in driving these variations in pituitary function is still controversial due to difficulties in measuring the secretion of the hypophysiotropic factors. Therefore, the mechanisms by which hyper-or hypoglycemia exerts an influence on hypothalamic neurons remain to be determined. In this report, we will briefly review this tropic including some results from our laboratory, keeping in mind the potential clinical applications of animal studies.

The hypothalamic regulation of ACTH secretion has been reviewed. Recent biochemical investigations on corticotropin-releasing factor (CRF) suggest that CRF is present in the hypothalamus under two or more different molecular weight forms, their structure being not elucidated yet. Vasopressin has a CRF-like activity. However, contradictory results have been reported on the role of AVP as a physiological CRF. The synthesis of CRF appears to occur in a large hypothalamic area outside the median eminence. CRF-carrying fibers are thought to pass through the lateral retrochiasmatic area and project on the hypophysial portal vessels at the junction between the pituitary stalk and the median eminence. Conflicting data have been published on the influence of monoamines on ACTH secretion. In the dog, ACTH release is inhibited by the α-adrenergic receptors, this effect being not as clearly demonstrated in other species. The stimulation of nicotinic and muscarinic receptors is followed by increased ACTH secretion. Glucocorticoids appear to lower ACTH secretion through an action at both the hypothalamic and pituitary levels.

Brattleboro rats which lack endogenous vasopressin have been used to study the role of vasopressin as a corticotropin-releasing factor. Plasma ACTH,β-endorphin, and corticosterone were measured by RIA in male and female Long- Evans and Brattleboro rats under the following conditions: unstressed, after ether stress, after nicotine injection, and after adrenalectomy. A significant reduction in the ACTH, β-endorphin, and corticosterone responses to the different experimental procedures was observed in the Brattleboro rats. However, in this strain of rats, a significant increase in the release of all three hormones was obtained, suggesting that vasopressin has only a synergistic role in the regulation of their secretion.

Three human pheochromocytomas obtained shortly after resection were analyzed for methionine- and leucine-enkephalin and enkephalin-containing proteins as well as ACTH, α-MSH, β-endorphin and catecholamines. The pheochromocytomas contained 0.8–13 nmol per gm wet weight of methionine-enkephalin, a concentration about 1000 times lower than the norepinephrine concentrations measured in the same tissues. Leucine-enkephalin levels were 9 to 33% those of methionine-enkephalin, whereas ACTH, α-MSH and β-endorphin were present in concentrations 150–2800 times lower than corresponding leucine-enkephalin levels. The human pheochromocytomas were also found to contain 14,000 and 2–5000 dalton enkephalin-containing proteins.

Plasma adrenocorticotropic hormone (ACTH) and corticosterone were detectable in fetal plasma on day 16 of pregnancy. Thereafter, the levels of both hormones increased steadily in a parallel manner and reached a peak on day 19 of pregnancy. Administration of an antiserum anti-rat corticotropin-releasing factor (CRF) to pregnant rats was followed by a significant decrease in fetal plasma corticosterone as early as day 17. Plasma ACTH measured under the same experimental conditions on day 19 of gestation was also significantly decreased. Similar results have been obtained with fetal plasma collected from adrenalectomized pregnant rats, indicating that the plasma corticosterone decrease in fetuses after immunoneutralization of CRF reflects changes in fetal adrenal secretion and not a diminution of corticosterone transfer from the maternal to the fetal circulation. These results show that endogenous CRF begins to play a physiological role in the regulation of ACTH and corticosterone secretion as early as in 17-day-old fetuses. This effect may occur before the connections between the neurosecretory CRF axons and the hypophysial portal capillaries have been established. Therefore, endogenous CRF may enter the hypophysial portal circulation after intercellular diffusion in hypothalamic tissue.

Corticosterone, ACTH, β-endorphin and α-MSH were measured in rat plasma by radioimmunoassay before and 2,5,15,30 minutes after an intraperitoneal injection of nicotine (500 μg/Kg b.w.). Nicotine induced an increase of plasma corticosterone (p