Document Detail

mTOR is Frequently Active in GH-Secreting Pituitary Adenomas without Influencing their Morphopathological Features.
MedLine Citation:
PMID:  23296986     Owner:  NLM     Status:  Publisher    
Initiating factors and mechanisms of tumor formation are poorly understood in nonfamilial pituitary adenomas. Alteration of intracellular pathways is an underlying event in numerous neoplasms. Among them, excessive activation of mammalian target of rapamycin (mTOR) pathway and its two main regulators, Akt and Erk, has been detected frequently in solid tumors. This study tests the activation of mTOR pathway in pituitary adenomas and its influence on their morphopathological features. Fifty-three pituitary adenomas were fresh frozen after surgery and analyzed by western blotting using phospho-specific antibodies. The impact of Akt and Erk activation on mTOR pathway was assessed in five primary cultures derived from the excised adenomas using selective kinase inhibitors. Statistical correlations of size, volume, Ki-67 %, Knosp's grading, and somatostatin receptor (SSTR) expression with the activation of mentioned kinases was performed. GHomas showed the highest frequency (71 %) and level of mTOR pathway activity comparing to other adenomas (33 %). No significant correlation was found between mTOR activation and any of the morphopathological features in the studied samples. mTOR kinase phosphorylation was independent of Erk and Akt in primary cultures. Erk activity was significant in all types of adenomas but was the highest in control samples. Its phosphorylation correlated inversely with the Knosp's grading in nonfunctional pituitary adenomas and directly with somatostatin receptor subtype 2 A expression in GHomas. Presented data point to the noteworthy mTOR activity in GHomas. However, the lack of correlation with morphopathological features, its independence of Erk and Akt phosphorylation, and high level of Erk activity in control pituitary necessitate further research for clarifying the role of these pathways in pituitary adenomas.
Emir Ahmed Sajjad; Grzegorz Zieliński; Maria Maksymowicz; Lukasz Hutnik; Tomasz Bednarczuk; Paweł Włodarski
Related Documents :
23345546 - The role of met receptor tyrosine kinase in non-small cell lung cancer and clinical dev...
12894516 - Modulation by the atp/gtp ratio of the phosphorylation level of p-glycoprotein and of v...
8447426 - Activation of phospholipase d in rat type ii pneumocytes by atp and other surfactant se...
10812616 - Immunoassay protocol for quantitation of protein kinase activities.
24052256 - Protein phosphatase 2a isoforms utilizing aβ scaffolds regulate differentiation throug...
2946706 - Association of tyrosine protein kinase activity with mitochondria in human fibroblasts.
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-8
Journal Detail:
Title:  Endocrine pathology     Volume:  -     ISSN:  1559-0097     ISO Abbreviation:  Endocr. Pathol.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-8     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9009288     Medline TA:  Endocr Pathol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Department of Histology and Embryology, Center for Biostructure Research, Medical University of Warsaw, Chałubińskiego 5, 02-004, Warszawa, Poland.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Detection of influent virulence and resistance genes in microarray data through quasi likelihood mod...
Next Document:  Coordination-Driven Switching of a Preorganized and Cooperative Calix[4]pyrrole Receptor.