scholarly journals Pituitary tumours: findings from whole genome analyses

2006 ◽  
Vol 13 (3) ◽  
pp. 707-716 ◽  
Author(s):  
W E Farrell
Keyword(s):  
Animal Models ◽  
New Technologies ◽  
Pituitary Tumour ◽  
Comparative Genomic ◽  
Whole Genome ◽  
Pituitary Tumours ◽  
Novel Genes ◽  
Human Pituitary ◽  
Genome Wide ◽  
Pituitary Tumorigenesis

Pituitary tumours are common intracranial neoplasms that cause significant morbidity through mass effects and/or the inappropriate secretion of pituitary hormones. Despite a considerable literature detailing potential pathogenic changes in these tumours, their aetiology remains largely unresolved. Recent studies have employed genome-wide profiling towards the identification of novel genes and pathways that are inappropriately expressed or regulated in this tumour type. The techniques employed vary in their complexity and interpretation; however, many of the findings from these types of studies have identified novel genes with potential and, in some cases, proven roles in pituitary tumorigenesis. These studies include comparative genomic hybridization, whole genome-wide allelotyping and methodologies for identification of novel genes associated with epigenetic silencing. In addition, differential display methodologies have been instrumental in the identification of transcripts inappropriately expressed including, pituitary tumour transforming gene, growth arrest and DNA damage-inducible protein (GADD)45γ and a maternal expressed gene 3 isoform, which in some cases have proven roles in pituitary tumorigenesis. Although few studies of whole genome transcript analysis, as determined by microarray or gene-chip technologies, are reported, these studies of human pituitary, in some cases combined with proteomics, are yielding useful data. In addition, these types of investigation have been applied to several animal models of pituitary tumorigenesis, and in these cases novel genes are highlighted as showing significant change. The identification of the initiating events responsible for the transformation of a normal pituitary cell into one with unrestrained proliferative capacity has so far eluded us. No doubt, these new technologies allowing an essentially unbiased genome-wide analysis, perhaps in combination with animal models that display a preceding hyperplasia, will allow us to identify genes critical to tumour evolution and progression.

scholarly journals Correlation of VEGF production with IL1α and IL6 secretion by human pituitary adenoma cells

2005 ◽  
Vol 152 (2) ◽  
pp. 293-300 ◽  
Author(s):  
S A Borg ◽  
K E Kerry ◽  
J A Royds ◽  
R D Battersby ◽  
T H Jones
Keyword(s):  
Pituitary Adenoma ◽  
Tumour Volume ◽  
Pituitary Tumour ◽  
Angiogenic Factor ◽  
Tumour Cell Line ◽  
Pituitary Tumours ◽  
Human Pituitary ◽  
Human Pituitary Adenoma ◽  
Invasive Status ◽  
Significant Addition

Objectives: Vascular endothelial growth factor (VEGF) is considered to be the most important angiogenic factor involved in the neovascularisation of solid tumours. Regulatory molecules include cytokines and growth factors. Interleukin (IL)1 and IL6 have both been shown to regulate VEGF levels in a variety of tissues. The role of cytokines in the pathogenesis of pituitary tumours remains unclear. We have examined the expression of VEGF and its relationships with IL1 and IL6 in the human pituitary tumour cell line HP75 and a series of human pituitary tumours. We have also looked at the relationship of tumour volume and invasive status to VEGF secretion. Methods: Surgically resected tumours were routinely cultured in single-cell suspension at 200 K/well (standard unit for culture of dispersed primary pituitary adenoma cells). We measured VEGF, IL1α and IL6 levels by ELISA. Tumour volume and invasion grade were assessed by preoperative magnetic resonance imaging. Results: VEGF was detected in conditioned medium of HP75 cells (900±52 pg/ml) and in 82% of tumours tested (range 26–16 464 pg/ml). Tumour volume and secretion of VEGF were significantly associated with levels of IL6 (volume, P = 0.056; VEGF, P < 0.001 (P values based on Spearman’s test)) and IL1α produced (volume, P < 0.005; VEGF, P < 0.001). Invasive tumours showed a higher basal secretion of VEGF that that of the non-invasive type; however, this difference was not significant. Addition of exogenous IL1α, but not IL6, significantly increased VEGF production. Conclusions: The significant associations between VEGF and the levels of IL6 and IL1α suggest an important role for these cytokines in the development of these tumours.

scholarly journals PTTG--a new pituitary tumour transforming gene

1999 ◽  
Vol 162 (2) ◽  
pp. 163-166 ◽  
Author(s):  
CJ McCabe ◽  
NJ Gittoes
Keyword(s):  
Cell Transformation ◽  
Pituitary Tumour ◽  
Strongly Correlated ◽  
Pituitary Tumours ◽  
Acid Protein ◽  
Pituitary Tumorigenesis ◽  
Acute Myelogenous ◽  
Transforming Gene ◽  
Amino Acid Protein

The pathogenesis of sporadic pituitary tumours remains elusive. Recently, a new candidate gene has been described which is able to induce pituitary cell transformation, and the expression of which appears to be strongly correlated with pituitary tumorigenesis. The so-called pituitary tumour transforming gene (PTTG) encodes a 23 kDa, 202 amino acid protein, and is located on chromosome 5q33, a locus previously associated with recurrent lung cancer and acute myelogenous leukaemias. Although the precise function of PTTG protein is unknown, in vitro experiments have demonstrated that it is capable of inducing fibroblast growth factor (FGF) expression. Mutation of the two proline-rich domains of the PTTG protein has also been shown to abolish subsequent FGF induction. Furthermore, in patients with pituitary adenomas, serum FGF concentrations fall post-operatively after successful excision of the tumour.

scholarly journals Natriuretic Peptide Expression and Function in GH3 Somatolactotropes and Feline Somatotrope Pituitary Tumours

2021 ◽  
Vol 22 (3) ◽  
pp. 1076
Author(s):  
Samantha M. Mirczuk ◽  
Christopher J. Scudder ◽  
Jordan E. Read ◽  
Victoria J. Crossley ◽  
Jacob T. Regan ◽  
...  
Keyword(s):  
Natriuretic Peptide ◽  
Natriuretic Peptides ◽  
Tumour Volume ◽  
Pituitary Tumour ◽  
Gh3 Cells ◽  
Loss Of Function ◽  
Pituitary Tumours ◽  
Human Pituitary ◽  
Oestrogen Treatment ◽  
And Function

Patients harbouring mutations in genes encoding C-type natriuretic peptide (CNP; NPPC) or its receptor guanylyl cyclase B (GC-B, NPR2) suffer from severe growth phenotypes; loss-of-function mutations cause achondroplasia, whereas gain-of-function mutations cause skeletal overgrowth. Although most of the effects of CNP/GC-B on growth are mediated directly on bone, evidence suggests the natriuretic peptides may also affect anterior pituitary control of growth. Our previous studies described the expression of NPPC and NPR2 in a range of human pituitary tumours, normal human pituitary, and normal fetal human pituitary. However, the natriuretic peptide system in somatotropes has not been extensively explored. Here, we examine the expression and function of the CNP/GC-B system in rat GH3 somatolactotrope cell line and pituitary tumours from a cohort of feline hypersomatotropism (HST; acromegaly) patients. Using multiplex RT-qPCR, all three natriuretic peptides and their receptors were detected in GH3 cells. The expression of Nppc was significantly enhanced following treatment with either 100 nM TRH or 10 µM forskolin, yet only Npr1 expression was sensitive to forskolin stimulation; the effects of forskolin and TRH on Nppc expression were PKA- and MAPK-dependent, respectively. CNP stimulation of GH3 somatolactotropes significantly inhibited Esr1, Insr and Lepr expression, but dramatically enhanced cFos expression at the same time point. Oestrogen treatment significantly enhanced expression of Nppa, Nppc, Npr1, and Npr2 in GH3 somatolactotropes, but inhibited CNP-stimulated cGMP accumulation. Finally, transcripts for all three natriuretic peptides and receptors were expressed in feline pituitary tumours from patients with HST. NPPC expression was negatively correlated with pituitary tumour volume and SSTR5 expression, but positively correlated with D2R and GHR expression. Collectively, these data provide mechanisms that control expression and function of CNP in somatolactotrope cells, and identify putative transcriptional targets for CNP action in somatotropes.

Epigenetic change in pituitary tumorigenesis.

2003 ◽  
pp. 323-330 ◽  
Author(s):  
W E Farrell ◽  
R N Clayton
Keyword(s):  
Cpg Islands ◽  
Pituitary Tumour ◽  
Histone Deacetylation ◽  
Pituitary Tumours ◽  
Kinase Gene ◽  
Expected Frequency ◽  
Cpg Dinucleotides ◽  
Pituitary Tumorigenesis ◽  
Frequent Event ◽  
Death Associated Protein Kinase

Throughout the genome CpG dinucleotides are found at one-fifth of their expected frequency and their rarity is further marked by the fact that 70% are methylated. In contrast, CpG islands (CGI), found associated with the promoters of many genes, have maintained their expected frequency of this dinucleotide, and remain unmethylated. Inappropriate methylation of CGIs is associated with histone deacetylation and gene silencing, while methylation of CpGs outside of CGIs is associated with significantly higher mutation rates. Methylation of CGIs is a frequent event in numerous tumour types including those that arise within the pituitary gland. Several studies now show highly frequent methylation of the p16 gene that is significantly associated with loss of cognate protein and that appears to be an early change in pituitary tumorigenesis. Collectively, studies show that somatotrophinomas are an infrequent target for p16 CGI methylation. However, in this pituitary tumour subtype, loss of pRb is associated with either CGI methylation or micro-deletion within the protein-pocket binding domain. As in other tumour types loss of p16 or RB1 appear to be mutually exclusive events in non-functional adenomas and somatotrophinomas respectively. Investigation of the Death Associated Protein Kinase gene shows that loss of its protein (DAPK), a pro-apoptotic molecule, in pituitary tumours is also associated with either methylation or deletion within its associated CGI. In the case of DAPK, however, these changes segregate with invasive pituitary tumours irrespective of tumour subtype. Methylation represents a positive signal that can be detected with exquisite sensitivity; in addition, this change targets multiple genes that show tumour type specificity. Taken together, the detection of DNA methylation changes, using either a panel of predefined marker-islands, or CGI arrays, provides the opportunity to generate "methylation profiles". This new knowledge will increase our understanding of tumour biology and could ultimately aid medical management in these different tumour types, including those of pituitary origin.

scholarly journals Array-Based Comparative Genomic Hybridization Application for Revealing Genomic Micro Imbalances in Congenital Malformations

2009 ◽  
Vol 12 (1) ◽  
pp. 3-8
Author(s):  
S Hadjidekova ◽  
D Toncheva
Keyword(s):  
Comparative Genomic Hybridization ◽  
Congenital Malformations ◽  
Comparative Genomic ◽  
Whole Genome ◽  
Industrialized Countries ◽  
Genomic Hybridization ◽  
Genomic Imbalances ◽  
Genome Wide ◽  
Genomic Location ◽  
The Impact

Array-Based Comparative Genomic Hybridization Application for Revealing Genomic Micro Imbalances in Congenital MalformationsBirth defects affect 3-5% of live births and are a major cause of fetal, neonatal and infant morbidity and mortality in all industrialized countries. Some 40-60% of congenital physical anomalies in humans have no cause, 20% that seem to be multifactorial, 10-13% environmental and 12-25% genetic.Classical cytogenetic or common comparative genomic hybridization (CGH) methods have limited use in investigation of the whole genome because of their low resolution (5-10 Mb). Fluorescence in situ hybridization (FISH) and quantitative fluorescence polymerase chain reaction (QF-PCR) have higher resolution but do not allow genome-wide screening and require some prior knowledge regarding the suspected chromosomal abnormality and its genomic location.Because of these limitations, the impact of genetic micro imbalances as etiological factors for the development of congenital malformations (CM) is underestimated. Array-based techniques have enabled higher resolution screens for genomic imbalances in CM as they permit identification of micro aberrations with a size between 60 bp and several hundred kilobases. They make possible screening of the whole genome and detection of novel unbalanced micro structural rearrangements in a single reaction and also effective screening of new dose-dependent genes. In addition, the application of the aCGH technology has the potential to improve our understanding of the normal quantitative variants of the human genome.

PIT1 upregulation by HMGA proteins has a role in pituitary tumorigenesis

2011 ◽  
Vol 19 (2) ◽  
pp. 123-135 ◽  
Author(s):  
Dario Palmieri ◽  
Teresa Valentino ◽  
Ivana De Martino ◽  
Francesco Esposito ◽  
Paolo Cappabianca ◽  
...  
Keyword(s):  
Pituitary Adenomas ◽  
Gene Promoter ◽  
Pituitary Tumour ◽  
Human Pituitary ◽  
Expression Levels ◽  
Pituitary Tumorigenesis ◽  
Its Gene ◽  
Gland Development

We have previously demonstrated that HMGA1B and HMGA2 overexpression in mice induces the development of GH and prolactin (PRL) pituitary adenomas mainly by increasing E2F1 transcriptional activity. Interestingly, these adenomas showed very high expression levels of PIT1, a transcriptional factor that regulates the gene expression ofGh,Prl,GhrhrandPit1itself, playing a key role in pituitary gland development and physiology. Therefore, the aim of our study was to identify the role ofPit1overexpression in pituitary tumour development induced by HMGA1B and HMGA2. First, we demonstrated that HMGA1B and HMGA2 directly interact with both PIT1 and its gene promoterin vivo, and that these proteins positively regulatePit1promoter activity, also co-operating with PIT1 itself. Subsequently, we showed, by colony-forming assays on two different pituitary adenoma cell lines, GH3 and αT3, thatPit1overexpression increases pituitary cell proliferation. Finally, the expression analysis ofHMGA1,HMGA2andPIT1in human pituitary adenomas of different histological types revealed a direct correlation betweenPIT1and HMGA expression levels. Taken together, our data indicate a role ofPit1upregulation by HMGA proteins in pituitary tumours.

Establishment of a genome-wide RNAi screen; Identification of novel genes involved in clonal maintenance of ALL

2014 ◽  
Vol 226 (03) ◽  
Author(s):  
F Ponthan ◽  
D Pal ◽  
J Vormoor ◽  
O Heidenreich
Keyword(s):  
Rnai Screen ◽  
Novel Genes ◽  
Genome Wide ◽  
A Genome

A critical reappraisal of MIB-1 labelling index significance in a large series of pituitary tumours: secreting versus non-secreting adenomas.

2002 ◽  
pp. 103-113 ◽  
Author(s):  
M L Jaffrain-Rea ◽  
D Di Stefano ◽  
G Minniti ◽  
V Esposito ◽  
A Bultrini ◽  
...  
Keyword(s):  
Operative Treatment ◽  
Hormone Secretion ◽  
Tumour Volume ◽  
Pituitary Tumour ◽  
Labelling Index ◽  
Pituitary Tumours ◽  
Life Threatening ◽  
The Mean ◽  
Monoclonal Antibody Mib 1 ◽  
Mib 1

Pituitary tumours are usually benign neoplasia, but may have a locally aggressive or malignant evolution. This study aimed to identify factors which mostly influence their proliferative activity, in order to clarify its value for clinical and research purposes. The proliferative index was determined in a prospective series of 132 pituitary tumours as the percentage of monoclonal antibody MIB-1-immunopositive cells and referred to as the MIB-1 labelling index (LI). Its distribution was analysed according to both univariate and multivariate models. A life-threatening pituitary tumour is presented separately. The mean LI was 1.24+/-1.59%, with significant differences between clinically secreting (CS) and clinically non-secreting (CNS) adenomas. In CS adenomas (n=65), LI was highly variable and markedly influenced by pre-operative pharmacological treatment (0.80+/-1.03 vs 2.06+/-2.39% in treated vs untreated cases, P=0.009); it decreased with patient's age (P=0.025, r=0.28) and increased with tumour volume and invasiveness. The influence of pre-operative treatment and macroscopic features on LI in this group was confirmed by multivariate analysis. In CNS adenomas (n=67), LI distribution was less variable than in CS adenomas (P<0.0001), it was age-independent and correlations with tumour volume, invasiveness or recurrence did not reach significance. In a rapidly growing parasellar tumour, the mean LI was 24% at first surgery and exceeded 50% at second surgery performed 4 months later. LI should be interpreted according to hormone secretion and pre-operative treatment. Unusually high LI values deserve particular attention.

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