Research IndicatorsGraph generated 25 June 2015 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 25 June, 2015 using data from PubMed, MeSH and CancerIndex
Specific Cancers (3)
Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
Search the Epigenomics database and view relevant gene tracks of samples.
Latest Publications: POU1F1 (cancer-related)
Diaz-Rodriguez E, Garcia-Rendueles AR, Ibáñez-Costa A, et al.Somatotropinomas, but not nonfunctioning pituitary adenomas, maintain a functional apoptotic RET/Pit1/ARF/p53 pathway that is blocked by excess GDNF.
Endocrinology. 2014; 155(11):4329-40 [PubMed
] Related Publications
Acromegaly is caused by somatotroph cell adenomas (somatotropinomas [ACROs]), which secrete GH. Human and rodent somatotroph cells express the RET receptor. In rodents, when normal somatotrophs are deprived of the RET ligand, GDNF (Glial Cell Derived Neurotrophic Factor), RET is processed intracellularly to induce overexpression of Pit1 [Transcription factor (gene : POUF1) essential for transcription of Pituitary hormones GH, PRL and TSHb], which in turn leads to p19Arf/p53-dependent apoptosis. Our purpose was to ascertain whether human ACROs maintain the RET/Pit1/p14ARF/p53/apoptosis pathway, relative to nonfunctioning pituitary adenomas (NFPAs). Apoptosis in the absence and presence of GDNF was studied in primary cultures of 8 ACROs and 3 NFPAs. Parallel protein extracts were analyzed for expression of RET, Pit1, p19Arf, p53, and phospho-Akt. When GDNF deprived, ACRO cells, but not NFPAs, presented marked level of apoptosis that was prevented in the presence of GDNF. Apoptosis was accompanied by RET processing, Pit1 accumulation, and p14ARF and p53 induction. GDNF prevented all these effects via activation of phospho-AKT. Overexpression of human Pit1 (hPit1) directly induced p19Arf/p53 and apoptosis in a pituitary cell line. Using in silico studies, 2 CCAAT/enhancer binding protein alpha (cEBPα) consensus-binding sites were found to be 100% conserved in mouse, rat, and hPit1 promoters. Deletion of 1 cEBPα site prevented the RET-induced increase in hPit1 promoter expression. TaqMan qRT-PCR (real time RT-PCR) for RET, Pit1, Arf, TP53, GDNF, steroidogenic factor 1, and GH was performed in RNA from whole ACRO and NFPA tumors. ACRO but not NFPA adenomas express RET and Pit1. GDNF expression in the tumors was positively correlated with RET and negatively correlated with p53. In conclusion, ACROs maintain an active RET/Pit1/p14Arf/p53/apoptosis pathway that is inhibited by GDNF. Disruption of GDNF's survival function might constitute a new therapeutic route in acromegaly.
Kubo S, Takagi-Kimura M, Logg CR, Kasahara NHighly efficient tumor transduction and antitumor efficacy in experimental human malignant mesothelioma using replicating gibbon ape leukemia virus.
Cancer Gene Ther. 2013; 20(12):671-7 [PubMed
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Retroviral replicating vectors (RRVs) have been shown to achieve efficient tumor transduction and enhanced therapeutic benefit in a wide variety of cancer models. Here we evaluated two different RRVs derived from amphotropic murine leukemia virus (AMLV) and gibbon ape leukemia virus (GALV), in human malignant mesothelioma cells. In vitro, both RRVs expressing the green fluorescent protein gene efficiently replicated in most mesothelioma cell lines tested, but not in normal mesothelial cells. Notably, in ACC-MESO-1 mesothelioma cells that were not permissive for AMLV-RRV, the GALV-RRV could spread efficiently in culture and in mice with subcutaneous xenografts by in vivo fluorescence imaging. Next, GALV-RRV expressing the cytosine deaminase prodrug activator gene showed efficient killing of ACC-MESO-1 cells in a prodrug 5-fluorocytosine dose-dependent manner, compared with AMLV-RRV. GALV-RRV-mediated prodrug activator gene therapy achieved significant inhibition of subcutaneous ACC-MESO-1 tumor growth in nude mice. Quantitative reverse transcription PCR demonstrated that ACC-MESO-1 cells express higher PiT-1 (GALV receptor) and lower PiT-2 (AMLV receptor) compared with normal mesothelial cells and other mesothelioma cells, presumably accounting for the distinctive finding that GALV-RRV replicates much more robustly than AMLV-RRV in these cells. These data indicate the potential utility of GALV-RRV-mediated prodrug activator gene therapy in the treatment of mesothelioma.
Akcay A, Ulucan K, Taskin N, et al.Suprasellar mass mimicking a hypothalamic glioma in a patient with a complete PROP1 deletion.
Eur J Med Genet. 2013; 56(8):445-51 [PubMed
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Mutations in PROP1 are the most frequent defect detected in patients with combined pituitary hormone deficiency (MIM #262600), characterized by a clinical phenotype of proportionate growth deficit due to impaired production of growth hormone in combination with deficiency of one or more of the additional anterior pituitary hormones. Approximately one third of patients with PROP1 inactivating mutations present with abnormal development of the anterior lobe of the pituitary gland as revealed by MRI. We report on the clinical and molecular characterization of the fourth complete PROP1 deletion in a girl with proportional short stature, combined pituitary hormone deficiency and a suprasellar mass mimicking a hypothalamic glioma. The proband, born to consanguineous parents, presented with proportional growth failure (height 108.8 cm, -3.48 SDS), combined pituitary hormone deficiency (GH, TSH, PRL and gonadotropins) and a suprasellar mass with optic chiasm invasion, compatible with a diagnosis of chiasmatic hypothalamic glioma, as revealed by MRI. PROP1 mutation screening by PCR and MLPA detected a homozygous deletion of the entire PROP1. The deletion was delimited to at least 7.7 kb upstream of PROP1 and more finely to ∼541-74 bp downstream from PROP1 by aCGH and PCR mapping. We describe the fourth case with a complete PROP1 deletion in homozygosis. The apparent location of the respective 5' (within a highly repetitive region, rich in Alu sequences) and 3' (within an Alu sequence) breakpoints, suggests that the deletion may have arisen through homologous recombination. The differentiation between PROP1 mutation associated pituitary enlargements from craniopharyngioma, pituitary adenoma, dys-germinoma, or Rathke's pouch cyst, is critical for the correct patient management. It is important to recognize that PROP1 mutations can present associated with evolving pituitary masses and/or other MRI alterations of the pituitary during early childhood and that surgery is not indicated in these patients. Therefore, in the presence of combined pituitary hormone deficiency and a pituitary or hypothalamic mass, PROP1 analysis should be considered before referring the patient to a neurosurgeon.
Leukemia and lymphoma account for more than 60% of deaths in captive koalas (Phascolarctos cinereus) in northeastern Australia. Although the endogenizing gammaretrovirus koala endogenous retrovirus (KoRV) was isolated from these koalas, KoRV has not been definitively associated with leukemogenesis. We performed KoRV screening in koalas from the San Diego Zoo, maintained for more than 45 y with very limited outbreeding, and the Los Angeles Zoo, maintained by continuously assimilating captive-born Australian koalas. San Diego Zoo koalas are currently free of malignant neoplasias and were infected with only endogenous KoRV, which we now term subtype "KoRV-A," whereas Los Angeles Zoo koalas with lymphomas/leukemias are infected in addition to KoRV-A by a unique KoRV we term subtype "KoRV-B." KoRV-B is most divergent in the envelope protein and uses a host receptor distinct from KoRV-A. KoRV-B also has duplicated enhancer regions in the LTR associated with increased pathology in gammaretroviruses. Whereas KoRV-A uses the sodium-dependent phosphate transporter 1 (PiT1) as a receptor, KoRV-B employs a different receptor, the thiamine transporter 1 (THTR1), to infect cells. KoRV-B is transmitted from dam to offspring through de novo infection, rather than via genetic inheritance like KoRV-A. Detection of KoRV-B in native Australian koalas should provide a history, and a mode for remediation, of leukemia/lymphoma currently endemic in this population.
Araujo RV, Chang CV, Cescato VA, et al.PROP1 overexpression in corticotrophinomas: evidence for the role of PROP1 in the maintenance of cells committed to corticotrophic differentiation.
Clinics (Sao Paulo). 2013; 68(6):887-91 [PubMed
] Free Access to Full Article Related Publications
OBJECTIVE: The expression of transcription factors involved in early pituitary development, such as PROP1 and POU1F1, has been detected in pituitary adenoma tissues. In this study, we sought to characterize the transcriptional profiles of PROP1, POU1F1, and TBX19 in functioning and nonfunctioning pituitary adenomas in an attempt to identify their roles in tumorigenesis and hormone hypersecretion.
METHODS: RT-qPCR analyses were performed to assess the transcriptional pattern of PROP1, POU1F1, TBX19, and hormone-producing genes in tissue samples of corticotrophinomas (n=10), somatotrophinomas (n=8), and nonfunctioning adenomas (n=6).
RESULTS: Compared with normal pituitary tissue, POU1F1 was overexpressed in somatotrophinomas by 3-fold. PROP1 expression was 18-fold higher in corticotrophinomas, 10-fold higher in somatotrophinomas, and 3-fold higher in nonfunctioning adenomas. TBX19 expression was 27-fold higher in corticotrophinomas. Additionally, the level of TBX19 mRNA positively correlated with that of pro-opiomelanocortin (r=0.49, p=0.014).
CONCLUSIONS: Our data demonstrate that PROP1 is overexpressed in pituitary adenomas, mainly in corticotrophinomas. Together with previously published data showing that patients who harbor PROP1 loss-of-function mutations present a progressive decline in corticotrope function, our results support a role for PROP1 in pituitary tumor development and in the maintenance of cell lineages committed to corticotrophic differentiation.
With the advent of improved molecular biology techniques, the genetic basis of an increasing number of reproductive disorders has been elucidated. Mutations in at least 20 genes cause hypogonadotropic hypogonadism including Kallmann syndrome in about 35-40% of patients. The two most commonly involved genes are FGFR1 and CHD7. When combined pituitary hormone deficiency includes hypogonadotropic hypogonadism as a feature, PROP1 mutations are the most common of the six genes involved. For hypergonadotropic hypogonadism, mutations in 14 genes cause gonadal failure in 15% of affected females, most commonly in FMR1. In eugonadal disorders, activating FSHR mutations have been identified for spontaneous ovarian hyperstimulation syndrome; and WNT4 mutations have been described in mullerian aplasia. For other eugonadal disorders, such as endometriosis, polycystic ovary syndrome, and leiomyomata, specific germline gene mutations have not been identified, but some chromosomal regions are associated with the corresponding phenotype. Practical genetic testing is possible to perform in both hypogonadotropic and hypergonadotropic hypogonadism and spontaneous ovarian hyperstimulation syndrome. However, clinical testing for endometriosis, polycystic ovary syndrome, and leiomyomata is not currently practical for the clinician.
BACKGROUND: NUP98 gene rearrangements have been reported in acute myeloid leukemia, giving rise to fusion proteins that seem to function as aberrant transcription factors, and are thought to be associated with poor prognosis.
FINDINGS: A patient with treatment-related acute myeloid leukemia presented a t(3;11)(p11;p15) as the only cytogenetic abnormality. FISH and molecular genetic analyses identified a class 1 homeobox gene, POU1F1, located on chromosome 3p11, as the fusion partner of NUP98. In addition, we have found that the patient harbored an FLT3-ITD mutation, which most likely collaborated with the NUP98-POU1F1 fusion gene in malignant transformation.
CONCLUSIONS: We have identified POU1F1 as the NUP98 fusion partner in therapy-related AML with a t(3;11)(p11;p15). This is the first POU family member identified as a fusion partner in human cancer.
Doknic M, Pekic S, Civcic M, Popovic VClinical Case Seminar. Peculiar prolactinomas in patients with pituitary developmental gene mutations: from an adult endocrinologist perspective.
Hormones (Athens). 2012 Apr-Jun; 11(2):189-98 [PubMed
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CONTEXT: Congenital hypopituitarism is a syndrome which is associated with single or multiple pituitary hormone deficiencies. Mutations in a number of developmental genes have been linked to combined pituitary hormone deficiencies, the most common being mutation in the pituitary homeobox protein prophet of the Pit 1 gene (PROP1). PROP1 exhibits DNA-binding and transcriptional activities. On magnetic resonance imaging, most patients with PROP1 mutation have a hypoplastic pituitary gland. Occasionally, transient pituitary enlargement before definite involution is reported. Kallmann syndrome (KS) is a human developmental genetic disorder which is a clinically (isolated hypogonadotropic hypogonadism-IHH) and genetically heterogeneous disease. Routine neuroimaging in classical IHH is thought to be of limited clinical value and normal anatomy of the hypothalamic-pituitary region is often reported. For neither disorder are there many reports on imaging during adulthood. Nor are there any guidelines concerning long-term imaging follow-up in patients with developmental pituitary disorders.
OBJECTIVE: Our aim was to present unusual endocrine and imaging abnormalities which developed in adulthood in two patients with developmental pituitary disorders.
CASES: We report a female with combined pituitary hormone deficiencies (GH, TSH, gonadotropin and ACTH), except for prolactin, as a consequence of PROP1 mutation, and a male with KS (anosmia and IHH) due to Kal 2 gene (fibroblast growth factor receptor 1- FGFR1) mutation, both of whom in adulthood presented with prolactinomas.
CONCLUSION: Both patients with developmental gene mutations, after long-term correction of their sex steroid status, developed prolactinomas. Although the exact mechanism of pituitary tumorigenesis is not known, we speculate that sex steroids may have facilitated prolactinoma development from the prolactin cell pool which underwent uncontrolled proliferation in the setting of a developmental disorder.
Palmieri D, Valentino T, De Martino I, et al.PIT1 upregulation by HMGA proteins has a role in pituitary tumorigenesis.
Endocr Relat Cancer. 2012; 19(2):123-35 [PubMed
] Related Publications
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 of Gh, Prl, Ghrhr and Pit1 itself, playing a key role in pituitary gland development and physiology. Therefore, the aim of our study was to identify the role of Pit1 overexpression in pituitary tumour development induced by HMGA1B and HMGA2. First, we demonstrated that HMGA1B and HMGA2 directly interact with both PIT1 and its gene promoter in vivo, and that these proteins positively regulate Pit1 promoter activity, also co-operating with PIT1 itself. Subsequently, we showed, by colony-forming assays on two different pituitary adenoma cell lines, GH3 and αT3, that Pit1 overexpression increases pituitary cell proliferation. Finally, the expression analysis of HMGA1, HMGA2 and PIT1 in human pituitary adenomas of different histological types revealed a direct correlation between PIT1 and HMGA expression levels. Taken together, our data indicate a role of Pit1 upregulation by HMGA proteins in pituitary tumours.
INTRODUCTION: Activating mutations in exon 3 of the β-catenin gene are involved in the pathogenesis of adamantinomatous craniopharyngiomas. Recently, the interaction between β-catenin and PROP1 has been shown to be responsible for pituitary cell lineage determination. We hypothesized that dysregulated PROP1 expression could also be involved in the pathogenesis of craniopharyngiomas
OBJECTIVES: To determine whether dysregulated gene expression was responsible for tumor pathogenesis in adamantinomatous craniopharyngiomas, the β-catenin gene was screened for mutations, and the expression of the β-catenin gene and PROP1 was evaluated. β-catenin gene was amplified and sequenced from 14 samples of adamantinomatous craniopharyngiomas. PROP1 and β-catenin gene expression was assessed by real-time RT-PCR from 12 samples, and β-catenin immunohistochemistry was performed on 11 samples.
RESULTS: Mutations in the β-catenin gene were identified in 64% of the adamantinomatous craniopharyngiomas samples. Evidence of β-catenin gene overexpression was found in 71% of the tumors with β-catenin mutations and in 40% of the tumors without mutations, and β-catenin immunohistochemistry revealed a nuclear staining pattern for each of the analyzed samples. PROP1 expression was undetectable in all of the tumor samples.
CONCLUSION: We found evidence of β-catenin gene overexpression in the majority of adamantinomatous craniopharyngiomas, and we also detected a nuclear β-catenin staining pattern regardless of the presence of a β-catenin gene mutation. These results suggest that WNT signaling activation plays an important role in the pathogenesis of adamantinomatous craniopharyngiomas. Additionally, this study was the first to evaluate PROP1 expression in adamantinomatous craniopharyngiomas, and the absence of PROP1 expression indicates that this gene is not involved in the pathogenesis of this tumor, at least in this cohort.
Roche C, Rasolonjanahary R, Thirion S, et al.Inactivation of transcription factor pit-1 to target tumoral somatolactotroph cells.
Hum Gene Ther. 2012; 23(1):104-14 [PubMed
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The treatment of growth hormone (GH)- and prolactin (PRL)-secreting tumors resistant to current therapeutic molecules (somatostatin and dopamine analogues) remains challenging. To target these tumors specifically, we chose to inactivate a gene coding for a crucial factor in cell proliferation and hormonal regulation, specifically expressed in pituitary, by using a dominant-negative form of this gene involved in human pituitary deficiencies: transcription factor Pit-1 (POU1F1) mutated on arginine 271 to tryptophan (R271W). After lentiviral transfer, the effect of R271W was studied in vitro on human tumoral somatotroph and lactotroph cells and on the murine mammosomatotroph cell line GH4C1 and in vivo on GH4C1 subcutaneous xenografts in nude mice. R271W induced a decrease in GH and PRL hypersecretion by controlling the transcription of the corresponding hormones. This mutant decreased cell viability by an apoptotic mechanism and in vivo blocked the tumoral growth and GH secretion of xenografts obtained after transplantation of GH4C1 expressing mutant R271W. The strategy of using a dominant-negative form of a main factor controlling cell proliferation and hormonal secretion, and exclusively expressed in pituitary, seems promising for the gene therapy of human pituitary tumors and may be translated to other types of tumors maintaining some differentiation features.
The Pit-1 transcription factor (also know as POU1F1) plays a critical role in cell differentiation during organogenesis of the anterior pituitary in mammals and is a transcriptional activator for pituitary gene transcription. Increased expression of Pit-1 has been reported in human tumorigenic breast cells. Here, we found that Pit-1 overexpression or knockdown in human breast cancer cell lines induced profound phenotypic changes in the expression of proteins involved in cell proliferation, apoptosis, and invasion. Some of these protumorigenic effects of Pit-1 were mediated by upregulation of Snai1, an inductor of the epithelial-mesenchymal transition. In immunodeficient mice, Pit-1 overexpression induced tumoral growth and promoted metastasis in lung. In patients with invasive ductal carcinoma of the breast and node-positive tumor, high expression of Pit-1 was significantly correlated with Snai1 positivity. Notably, in these patients elevated expression of Pit-1 was significantly and independently associated with the occurrence of distant metastasis. These findings suggest that Pit-1 could help to make a more accurate prognosis in patients with node-positive breast cancer and may represent a new therapeutic target.
Carney complex (CNC) is an inherited tumor predisposition associated with pituitary tumors, including GH-producing pituitary adenomas and rare reports of prolactinomas. This disease is caused by mutations in PRKAR1A, which encodes the type 1A regulatory subunit of the cAMP-dependent protein kinase, PKA. Loss of PRKAR1A causes enhanced PKA signaling, which leads to pituitary tumorigenesis. Mutations in the gene have not been detected in sporadic pituitary tumors, but there is some data to suggest that non-genomic mechanisms may cause loss of protein expression. Unlike CNC patients, mice heterozygous for Prkar1a mutations do not develop pituitary tumors, although complete knockout of the gene in the Pit1 lineage of the pituitary produces GH-secreting pituitary adenomas. These data indicate that complete loss of Prkar1a/PRKAR1A is able to cause pituitary tumors in mice and men. The pattern of tumors is likely related to the signaling pathways employed in specific pituitary cell types.
Chang H, Rha SY, Jeung HC, et al.Identification of genes related to a synergistic effect of taxane and suberoylanilide hydroxamic acid combination treatment in gastric cancer cells.
J Cancer Res Clin Oncol. 2010; 136(12):1901-13 [PubMed
] Related Publications
PURPOSE: We evaluated the cytotoxic effects of combining suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, with taxanes in human gastric cancer cell lines and assessed the pre-treatment difference of gene expression to identify genes that could potentially mediate the cytotoxic response.
METHODS: Gastric cancer cell lines were treated with SAHA and paclitaxel or docetaxel, and the synergistic interaction between the drugs was evaluated in vitro using the combination index (CI) method. We performed significance analysis of microarray (SAM) to identify chemosensitivity-related genes in gastric cancer cell lines that were concomitantly treated with SAHA and taxane. We generated a correlation matrix between gene expression and CI values to identify genes whose expression correlated with a combined effect of taxanes and SAHA.
RESULTS: Combination treatment with taxane and SAHA had a synergistic cytotoxic effect against taxane-resistant gastric cancer cells. We identified 49 chemosensitivity-related genes via SAM analysis. Among them, nine common genes (SLIT2, REEP2, EFEMP2, CDC42SE1, FSD1, POU1F1, ZNF79, ETNK1, and DOCK5) were extracted from the subsequent correlation matrix analysis.
CONCLUSIONS: The combination of taxane and SAHA could be efficacious for the treatment of gastric cancer. The genes that were related to the synergistic response to taxane and SAHA could serve as surrogate biomarkers to predict the therapeutic response in gastric cancer patients.
Campanini ML, Colli LM, Paixao BM, et al.CTNNB1 gene mutations, pituitary transcription factors, and MicroRNA expression involvement in the pathogenesis of adamantinomatous craniopharyngiomas.
Horm Cancer. 2010; 1(4):187-96 [PubMed
] Related Publications
Genes involved in formation/development of the adenohypophysis, CTNNB1 gene, and microRNAs might be implicated in the craniopharyngioma pathogenesis. The objective of this study is to perform the molecular analysis of HESX1, PROP1, POU1F1, and CTNNB1 genes and evaluate a panel of miRNA expression in craniopharyngioma. We also verified whether the presence of CTNNB1 mutation is associated with clinical findings and miRNA expression. The study included 16 patients with adamantinomatous craniopharyngioma (nine children and seven adults; eight females and eight males; 6-55 years, median 15.5 years). DNA, RNA, and cDNA were obtained from craniopharyngioma and normal pituitaries. DNA was also extracted from peripheral blood of healthy subjects. All genes were amplified by polymerase chain reaction and direct sequenced. Relative quantification of miRNA expression was calculated using the 2(-ΔΔCt) method. We found no mutations in HESX1, PROP1, and POU1F1 genes and four polymorphisms in PROP1 gene which were in Hardy-Weinberg equilibrium and had similar allelic frequencies in craniopharyngioma and controls. We found seven different mutations in CTNNB1 in eight of 16 patients. Younger patients presented more frequently CTNNB1 mutation than adults. We observed hyperexpression of miR-150 (1.7-fold); no different expression of miR-16-1, miR-21, and miR23a; and an underexpression of miR-141, let-7a, miR-16, miR-449, miR-145, miR-143, miR-23b, miR-15a, and miR-24-2 (ranging from -7.5 to -2.5-fold; p = 0.02) in craniopharyngioma. There was no association between tumor size or the recurrence and the presence of CTNNB1mutations. miR-16 and miR-141 were underexpressed in craniopharyngioma presenting CTNNB1 mutations. miR-23a and miR24-2 were hyperexpressed in patients who underwent only one surgery. Mutations or polymorphisms in pituitary transcription factors are unlikely to contribute to the adamantinomatous craniopharyngioma pathogenesis, differently of CTNNB1 mutations. Our data suggest the potential involvement of the deregulation of miRNA expression in the craniopharyngioma pathogenesis and outcome and also that the miRNA could modulate the Wnt signaling pathway in craniopharyngioma tumorigenesis.
The transcription factor Pit-1/Pou1f1 regulates GH and prolactin (PRL) secretion in the pituitary gland. Pit-1 expression and GH regulation by Pit-1 have also been demonstrated in mammary gland. However, no data are available on the role of Pit-1 on breast PRL. To evaluate this role, several human breast cancer cell lines were transfected with either the Pit-1 expression vector or a Pit-1 small interference RNA construct, followed by PRL mRNA and protein evaluation. In addition, transient transfection of MCF-7 cells by a reporter construct containing the proximal PRL promoter, and ChIP assays were performed. Our data indicate that Pit-1 regulates mammary PRL at transcriptional level by binding to the proximal PRL promoter. We also found that Pit-1 raises cyclin D1 expression before increasing PRL levels, suggesting a PRL-independent effect of Pit-1 on cell proliferation. By using immunohistochemistry, we found a significant correlation between Pit-1 and PRL expression in 94 human breast invasive ductal carcinomas. Considering the possible role of PRL in breast cancer disorders, the function of Pit-1 in breast should be the focus of further research.
Zygmunt-Górska A, Starzyk J, Adamek D, et al.Pituitary enlargement in patients with PROP1 gene inactivating mutation represents cystic hyperplasia of the intermediate pituitary lobe. Histopathology and over 10 years follow-up of two patients.
J Pediatr Endocrinol Metab. 2009; 22(7):653-60 [PubMed
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Patients with a PROP1 inactivating mutation present combined pituitary hormone deficiency (CPHD) and pituitary maldevelopment. A retrospective analysis of 31 CPHD patients with a PROP1 mutation revealed two individuals, aged 18 and 4.5 years, who had undergone subtotal surgery to remove pituitary tumors, 16.8 x 12 mm and 9 x 10 x 12 mm in size. Histological reassessment of tissue samples revealed epithelial cells, partially oxyphilic, forming gland-like microcystic structures, most of them filled with eosinophilic colloid. These structures were directly linked with fragments of the posterior lobe. Neither atypia nor any traces of proliferation activity (Ki-67 LI=0%) were noted. Immunohistochemistry showed the presence of all hormonal phenotypes of cells. These findings corresponded to the intermediate lobe of the pituitary gland. For this type of pathology we propose the term 'cystic hyperplasia of the intermediate pituitary lobe' and suggest PROP1 gene assessment in patients with CPHD in order to avoid unnecessary neurosurgical interventions.
McKee Alderman J, DePetrillo MA, Gluesenkamp AM, et al.Calorie restriction and dwarf mice in gerontological research.
Gerontology. 2010; 56(4):404-9 [PubMed
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What aging process is delayed by calorie restriction (CR) and mutations that produce long-lived dwarf mice? From 1935 until 1996, CR was the only option for increasing the maximum lifespan of laboratory rodents. In 1996, the mutation producing the Ames dwarf mouse (Prop-1(-/-)) was reported to increase lifespan. Since 1996, other gene mutations that cause dwarfism or lower body weight have been reported to increase the lifespan of mice. The recent discovery of long-lived mutant dwarf mice provides an opportunity to investigate common features between CR and dwarf models. Both CR and dwarf mutations increase insulin sensitivity. Elevated insulin sensitivity reduces oxidative stress, a potential cause of aging. The elevation of liver insulin sensitivity by the hormone adiponectin in CR and long-lived dwarf mice can lower endogenous glucose production and raise fatty acid oxidation. Adiponectin reduction of plasma glucose in CR and long-lived dwarf mice can thereby lower age-related increases in oxidative damage and cancer.
Schittenhelm J, Psaras T, Honegger J, et al.No evidence for WT1 involvement in a beta-catenin-independent activation of the Wnt signaling pathway in pituitary adenomas.
Endocr Pathol. 2009; 20(3):158-62 [PubMed
] Related Publications
The overexpression of Wilms' tumor gene product WT1, which acts as a tumor suppressor or oncogene, has been reported in various malignancies. Recent studies have shown that the interaction partner Wnt-4 is upregulated in pituitary adenomas dependent on the Pit-1 lineage (somatotrophs, lactotrophs, and thyrotrophs). However, no data on WT1 expression in nontumorous pituitary tissue or pituitary adenomas is available to date. We investigated WT1 expression in 90 paraffin-embedded pituitary adenomas, including eight atypical adenomas, and in 28 nontumorous pituitary glands by immunohistochemistry. WT1 is absent in epithelial cells of all nontumorous pituitary glands and in 87 out of 90 pituitary adenomas. Only two GHomas (including one atypical adenoma) and one gonadotropin-producing adenoma expressed WT1 in the cytoplasm of single tumor cells without nuclear staining. There is no evidence that WT1 does regulate the Wnt-4/beta-catenin-independent pathway which is activated in the Pit-1-expressing subset of pituitary adenomas.
Cody NA, Shen Z, Ripeau JS, et al.Characterization of the 3p12.3-pcen region associated with tumor suppression in a novel ovarian cancer cell line model genetically modified by chromosome 3 fragment transfer.
Mol Carcinog. 2009; 48(12):1077-92 [PubMed
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The genetic analysis of nontumorigenic radiation hybrids generated by transfer of chromosome 3 fragments into the tumorigenic OV-90 ovarian cancer cell line identified the 3p12.3-pcen region as a candidate tumor suppressor gene (TSG) locus. In the present study, polymorphic microsatellite repeat analysis of the hybrids further defined the 3p12.3-pcen interval to a 16.1 Mb common region containing 12 known or hypothetical genes: 3ptel-ROBO2-ROBO1-GBE1-CADM2-VGLL3-CHMP2B-POU1F1-HTR1F-CGGBP1-ZNF654-C3orf38-EPHA3-3pcen. Seven of these genes, ROBO1, GBE1, VGLL3, CHMP2B, CGGBP1, ZNF654, and C3orf38, exhibited gene expression in the hybrids, placing them as top TSG candidates for further analysis. The expression of all but one (VGLL3) of these genes was also detected in the parental OV-90 cell line. Mutations were not identified in a comparative sequence analysis of the predicted protein coding regions of these candidates in OV-90 and donor normal chromosome 3 contig. However, the nondeleterious sequence variants identified in the transcribed regions distinguished parent of origin alleles for ROBO1, VGLL3, CHMP2B, and CGGBP1 and cDNA sequencing of the hybrids revealed biallelic expression of these genes. Interestingly, underexpression of VGLL3 and ZNF654 were observed in malignant ovarian tumor samples as compared with primary cultures of normal ovarian surface epithelial cells or benign ovarian tumors, and this occurred regardless of allelic content of 3p12.3-pcen. The results taken together suggest that dysregulation of VGLL3 and/or ZNF654 expression may have affected pathways important in ovarian tumorigenesis which was offset by the transfer of chromosome 3 fragments in OV-90, a cell line hemizygous for 3p.
Miyakoshi T, Takei M, Kajiya H, et al.Expression of Wnt4 in human pituitary adenomas regulates activation of the beta-catenin-independent pathway.
Endocr Pathol. 2008; 19(4):261-73 [PubMed
] Related Publications
The Wnt signaling pathway has been implicated in the genesis of numerous human cancers. A member of the Wnt family of genes, Wnt4, has been known to regulate proliferation of anterior pituitary cell types in the mouse during embryonic development. In order to elucidate the roles of Wnt signaling in human pituitary adenomas, we examined the expression of Wnt4 and its putative receptor Frizzled6 (Fzd6) by immunohistochemistry in pituitary adenomas and normal pituitaries. Expression of Wnt4 was higher in growth hormone-producing adenomas (GHomas), prolactin-producing adenomas (PRLomas), and thyroid-stimulating hormone-producing adenomas (TSHomas) than in the normal pituitary. Fzd6 was widely expressed in GHomas, PRLomas, TSHomas, and gonadotropin subunit (GnSU)-positive adenomas. In normal pituitary glands, Wnt4 and Fzd6 were colocalized predominantly in follicle-stimulating hormone-, luteinizing hormone-, and alpha-subunits of glycoprotein hormone-positive cells. The canonical Wnt/beta-catenin signaling pathway was analyzed by beta-catenin immunohistochemistry. beta-Catenin was localized at the cell membrane in all pituitary adenomas, but not in the nuclei. On the other hand, Erk1/2 was highly activated in GHomas and TSHomas. These results suggested that activation of Wnt4/Fzd6 signaling through a "beta-catenin-independent" pathway played a role in proliferation and survival of the pituitary adenoma cells. Detailed involvement of transcription factors including Pit-1 remains to be further investigated.
Suzuki M, Egashira N, Kajiya H, et al.ACTH and alpha-subunit are co-expressed in rare human pituitary corticotroph cell adenomas proposed to originate from ACTH-committed early pituitary progenitor cells.
Endocr Pathol. 2008; 19(1):17-26 [PubMed
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The functional differentiation of pituitary cells and adenomas follows the combination of transcription factors and co-factors in three cell lineages [growth hormone-prolactin-thyroid-stimulating hormone lineage, adrenocorticotrophic hormone (ACTH)/pro-opiomelanocortin (POMC) lineage, and follicular stimulating hormone (FSH)/luteinizing hormone (LH) lineage], which include Pit-1, GATA-2, SF-1, NeuroD1/beta2, Tpit, ERalpha, and others. Only rarely are hormones from different lineages co-expressed in the same adenoma cells. Most corticotroph cell adenomas belonging to the ACTH/POMC lineage are mono-hormonal. In our study of 89 corticotroph cell adenomas, 5 cases expressed both ACTH and alpha-subunit; these adenomas did not express any other anterior pituitary hormones or subunits. To clarify the mechanism involved, we studied the transcription factors that regulate pituitary cell differentiation. NeuroD1 and T-pit, markers of the ACTH/POMC lineage, and SF-1 and DAX-1, related to the LH/FSH cell lineage were expressed in all cases. GATA2, a synergistic factor in the gonadotroph cell lineage with SF-1, was also expressed in three of five cases. As ACTH and alpha-subunit are the earliest hormones to appear during development, we speculate that these particular adenomas are derived from committed ACTH progenitor cells. The molecular process governing functional differentiation of these adenomas requires further investigation.
Evans CO, Moreno CS, Zhan X, et al.Molecular pathogenesis of human prolactinomas identified by gene expression profiling, RT-qPCR, and proteomic analyses.
Pituitary. 2008; 11(3):231-45 [PubMed
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The molecular pathogenesis of prolactinomas has resisted elucidation; with the exception of a RAS mutation in a single aggressive prolactinoma, no mutational changes have been identified. In prolactinomas, a further obstacle has been the paucity of surgical specimens suitable for molecular analysis since prolactionomas are infrequently removed due to the availability and effectiveness of medical therapy. In the absence of mutational events, gene expression changes have been sought and detected. Using high-throughput analysis from a large bank of human pituitary adenomas, we examined these tumors according to their molecular profiles rather than traditional immunohistochemistry. We examined six prolactinomas and eight normal pituitary glands using oligonucleotide GeneChip microarrays, reverse transcription-real time quantitative polymerase chain reaction using 10 prolactinomas, and proteomic analysis to examine protein expression in four prolactinomas. Microarray analyses identified 726 unique genes that were statistically significantly different between prolactinomas and normal glands, whereas proteomic analysis identified four differently up-regulated and 19 down-regulated proteins. Several components of the Notch pathway were altered in prolactinomas, and there was an increased expression of the Pit-1 transcription factor, and the survival factor BAG1 but decreased E-cadherin and N-cadherin expression. Taken together, expression profiling and proteomic analyses have identified molecular features unique to prolactinomas that may contribute to their pathogenesis. In the current era of molecular medicine, these findings greatly enhance our understanding and supercede immunohistochemical diagnosis.
Fratticci A, Grieco FA, Spilioti C, et al.Differential expression of neurogenins and NeuroD1 in human pituitary tumours.
J Endocrinol. 2007; 194(3):475-84 [PubMed
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Basic helix-loop-helix (bHLH) transcription factors are involved in neuroendocrine cell growth and differentiation. Though NeuroD1 is viewed as corticotroph specific, its overexpression in non-corticotroph pituitary adenomas (PAs) may reflect the activation of molecular pathways involving other bHLH factors, like neurogenins. To search for neurogenin-NeuroD1 molecular pathways in the human normal and tumoural pituitary. Fifty-one PAs--22 clinically non-secreting (CNS) and 29 secreting respectively--and normal human pituitaries (NP) were studied for NeuroD1 and neurogenins (Ngn1, Ngn2 and Ngn3) gene expression by RT-PCR and quantitative real-time RT-PCR (qRT-PCR). Immunohistochemistry for Ngn2/3 was performed in some cases. NeuroD1, Ngn2, Ngn3 and Ngn1 were observed in up to 84.3, 76.5, 30.4 and 9.1% of PA respectively, only NeuroD1 and Ngn2 being frequently overexpressed when compared with NP. Whereas NeuroD1 expression was higher in corticotroph and CNS adenomas (P=0.0001 versus Pit-1-dependent PA), Ngn2 expression was higher in secreting PA, especially in Pit-1-dependent PA (P=0.007 and P=0.0006 versus CNS respectively). Pit-1-dependent PA which received pre-operative pharmacological treatment expressed higher Ngn2 levels than untreated cases (P=0.025). Nuclear Ngn2 was observed in NP and in most PA, especially ACTH- and GH-secreting adenomas. Nuclear Ngn3 was observed in a minority of secreting PA. Ngn2 is normally expressed in the anterior pituitary and frequently expressed in PA, but does not account for NeuroD1 overexpression where present. Owing to their low and inconstant expression, the biological significance of Ngn1/3 in the adult pituitary is uncertain.
Seoane S, Ben I, Centeno V, Perez-Fernandez RCellular expression levels of the vitamin D receptor are critical to its transcriptional regulation by the pituitary transcription factor Pit-1.
Mol Endocrinol. 2007; 21(7):1513-25 [PubMed
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The biological role of 1,25-dihydroxyvitamin D(3) has generally been related to calcium homeostasis, but this hormone also has fundamental effects on processes of cellular proliferation and differentiation. The genomic actions of 1,25-dihydroxyvitamin D(3) are mediated by the vitamin D receptor (VDR) present in target cells. However, VDR transcriptional regulation is not well understood, probably attributable to the complexity of the VDR gene and its promoter. In the present study, it is demonstrated that administration of the pituitary transcription factor Pit-1 (originally found in the pituitary gland but also present in other nonpituitary cell types and tissues) to the MCF-7 (human breast adenocarcinoma) cell line induces a significant increase in VDR mRNA and protein levels. Conversely, Pit-1-targeted small interference RNA markedly reduced expression of VDR in MCF-7 cells. Reporter gene assays demonstrated that the effect of Pit-1 is mediated by its binding to a region located between -254 and -246 bp from the VDR transcription start site. Selective mutations of this site completely abolished VDR transcription. Chromatin immunoprecipitation analysis showed that binding of Pit-1 to the VDR promoter leads additionally to recruitment of cAMP response element-binding protein binding protein, acetylated histone H4, and RNA polymerase II. Surprisingly, Pit-1 binding also recruits VDR protein to the VDR promoter. Using several cell lines with different levels of VDR expression, it was demonstrated that up-regulation of VDR transcription by Pit-1 is dependent on the presence of VDR protein, suggesting that transcriptional expression of VDR in a given cell type is dependent on, among other factors, its own expression levels.
The complex pathogenesis of mineralization defects seen in inherited and/or acquired hypophosphatemic disorders suggests that local inorganic phosphate (P(i)) regulation by osteoblasts may be a rate-limiting step in physiological bone mineralization. To test whether an osteoblast autonomous phosphate regulatory system regulates mineralization, we manipulated well-established in vivo and in vitro models to study mineralization stages separately from cellular proliferation/differentiation stages of osteogenesis. Foscarnet, an inhibitor of NaP(i) transport, blocked mineralization of osteoid formation in osteoblast cultures and local mineralization after injection over the calvariae of newborn rats. Mineralization was also down- and upregulated, respectively, with under- and overexpression of the type III NaP(i) transporter Pit1 in osteoblast cultures. Among molecules expressed in osteoblasts and known to be related to P(i) handling, stanniocalcin 1 was identified as an early response gene after foscarnet treatment; it was also regulated by extracellular P(i), and itself increased Pit1 accumulation in both osteoblast cultures and in vivo. These results provide new insights into the functional role of osteoblast autonomous P(i) handling in normal bone mineralization and the abnormalities seen in skeletal tissue in hypophosphatemic disorders.
Dagvadorj A, Collins S, Jomain JB, et al.Autocrine prolactin promotes prostate cancer cell growth via Janus kinase-2-signal transducer and activator of transcription-5a/b signaling pathway.
Endocrinology. 2007; 148(7):3089-101 [PubMed
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The molecular mechanisms that promote progression of localized prostate cancer to hormone-refractory and disseminated disease are poorly understood. Prolactin (Prl) is a local growth factor produced in high-grade prostate cancer, and exogenously added Prl in tissue or explant cultures of normal and malignant prostate is a strong mitogen and survival factor for prostate epithelium. The key signaling proteins that mediate the biological effects of Prl in prostate cancer are Signal Transducer and Activator of Transcription (Stat)-5a/5b via activation of Janus kinase-2. Importantly, inhibition of Stat5a/b in prostate cancer cells induces apoptotic death. Using a specific Prl receptor antagonist (Delta1-9G129R-hPRL), we demonstrate here for the first time that autocrine Prl in androgen-independent human prostate cancer cells promotes cell viability via Stat5 signaling pathway. Furthermore, we examined a unique clinical material of human hormone refractory prostate cancers and metastases and show that autocrine Prl is expressed in 54% of hormone-refractory clinical human prostate cancers and 62% prostate cancer metastases. Finally, we demonstrate that autocrine Prl is expressed from both the proximal and distal promoters of the Prl gene in clinical human prostate cancers and in vivo and in vitro human prostate cancer models, independently of pituitary transcription factor-1 (Pit-1). Collectively, the data provide novel evidence for the concept that autocrine Prl signaling pathway is involved in growth of hormone-refractory and metastatic prostate cancer. The study also provides support for the use of Prl receptor antagonists or other therapeutic strategies to block the Prl-Janus kinase-2-Stat5 signaling pathway in advanced prostate cancer.
Somatotrophs are the only pituitary cells that express Ret, GFRalpha1 and GDNF. This study investigated the effects of Ret in a somatotroph cell line, in primary pituitary cultures and in Ret KO mice. Ret regulates somatotroph numbers by inducing Pit-1 overexpression, leading to increased p53 expression and apoptosis, both of which can be prevented with Ret or Pit-1 siRNA. The Pit-1 overexpression is mediated by sustained activation of PKCdelta, JNK, c/EBPalpha and CREB induced by a complex of Ret, caspase 3 and PKCdelta. In the presence of GDNF, Akt is activated, and the Pit-1 overexpression and resulting apoptosis are blocked. The adenopituitary of Ret KO mice is larger than normal, showing Pit-1 and somatotroph hyperplasia. In normal animals, activation of the Ret/Pit-1/p53 pathway by retroviral introduction of Ret blocked tumor growth in vivo. Thus, somatotrophs have an intrinsic mechanism for controlling Pit-1/GH production through an apoptotic/survival pathway. Ret might be of value for treatment of pituitary adenomas.
Quentien MH, Barlier A, Franc JL, et al.Pituitary transcription factors: from congenital deficiencies to gene therapy.
J Neuroendocrinol. 2006; 18(9):633-42 [PubMed
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Despite the existence of interspecies phenotypic variability, animal models have yielded valuable insights into human pituitary diseases. Studies on Snell and Jackson mice known to have growth hormone, prolactin and thyroid-stimulating hormone deficiencies involving the hypoplastic pituitary gland have led to identifying alterations of the pituitary specific POU homeodomain Pit-1 transcription factor gene. The human phenotype associated with rare mutations in this gene was found to be similar to that of these mice mutants. Terminal differentiation of lactotroph cells and direct regulation of the prolactin gene both require interactions between Pit-1 and cell type specific partners, including panpituitary transcriptional regulators such as Pitx1 and Pitx2. Synergistic activation of the prolactin promoter by Pitx factors and Pit-1 is involved not only in basal condition, but also in responsiveness to forskolin, thyrotrophin-releasing-hormone and epidermal growth factor. In corticotroph cells, Pitx1 interacts with Tpit. Tpit mutations have turned out to be the main molecular cause of neonatal isolated adrenocorticotrophin deficiency. This finding supports the idea that Tpit plays an essential role in the differentiation of the pro-opiomelanocortin pituitary lineage. The effects of Pit-1 are not restricted to hormone gene regulation because this factor also contributes to cell division and protects the cell from programmed cell death. Lentiviral vectors expressing a Pit-1 dominant negative mutant induced time- and dose-dependent cell death in somatotroph and lactotroph adenomas in vitro. Gene transfer by lentiviral vectors should provide a promising step towards developing an efficient specific therapeutic approach by which a gene therapy programme for treating human pituitary adenomas could be based.
Aikawa S, Sato T, Ono T, et al.High level expression of Prop-1 gene in gonadotropic cell lines.
J Reprod Dev. 2006; 52(2):195-201 [PubMed
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Prop-1 acts as an upstream regulator for the Pit-1 gene to induce development of Pit-1 lineage pituitary cell lines, GH-, PRL-, and TSH-producing cells, in the early stage of pituitary organogenesis. Furthermore, Prop-1 is presumed to be involved in the function of FSH/LH-producing cells, gonadotropes, since the defective Prop-1 gene shows hypogonadism. Recently, we reported evidence that Prop-1 directly regulates expression of the porcine FSHbeta gene, thus providing a novel advance in understanding the function of Prop-1 in FSH/LH production and hypogonadism. This study was intended to demonstrate the expressions of Prop-1 gene in pituitary tumor-derived cell lines. RT-PCR analyses were conducted of Pit-1, glycoprotein alpha subunit (alphaGSU), GnRH receptor, and cyclophilin A (a ubiquitously expressing gene). We observed expression of the Pit-1 gene in alphaT1-1, TalphaT1, MtT/S, GH3, and TtT/GF cells, expression of the alphaGSU gene in alphaT1-1, alphaT3-1, LbetaT2, LbetaT4, TalphaT1, and GH3 cells, and expression of GnRH receptor gene in alphaT3-1, LbetaT2, LbetaT4, and GH3 cells, respectively. These expression profiles were in accord with their cell lineages, with only a few exceptions. To accurately measure the expression level of the Prop-1 gene, a quantitative analysis was performed using the real-time PCR method. This analysis demonstrated that the LbetaT2 and LbetaT4 gonadotrope cell lines, which express the FSHbeta gene, express the Prop-1 gene. Taken together with our previous observation that Prop-1 is present in the adult porcine pituitary gonadotropes, Prop-1 might also be involved in development of gonadotropes and hormone production.