Novel molecular signaling and classification of human clinically nonfunctional pituitary adenomas identified by gene expression profiling and proteomic analyses
CANCER RESEARCH
Authors: Moreno, CS; Evans, CO; Zhan, XQ; Okor, M; Desiderio, DM; Oyesiku, NM
Abstract
Pituitary adenomas comprise 10% of intracranial tumors and occur in about 20% of the population. They cause significant morbidity by compression of regional structures or the inappropriate expression of pituitary hormones. Their molecular pathogenesis is unclear, and the current classification of clinically nonfunctional tumors does not reflect any molecular distinctions between the subtypes. To further elucidate the molecular changes that contribute to the development of these tumors and reclassify them according to the molecular basis, we investigated 11 nonfunctional pituitary adenomas and eight normal pituitary glands, using 33 oligonucleotide GeneChip microarrays. We validated microarray results with the reverse transcription real-time quantitative PCR, using a larger number of nonfunctional adenomas. We also used proteomic analysis to examine protein expression in these nonfunctional adenomas. Microarray analysis identified significant increases in the expression of 115 genes and decreases in 169 genes, whereas proteomic analysis identified 21 up-regulated and 29 down-regulated proteins. We observed changes in expression of SFRP1, TLE2, PITX2, NOTCH3, and DLK1, suggesting that the developmental Wnt and Notch pathways are activated and important for the progression of nonfunctional pituitary adenomas. We further analyzed gene expression profiles of all nonfunctional pituitary subtypes to each other and identified genes that were affected uniquely in each subtype. These results show distinct gene and protein expression patterns in adenomas, provide new insight into the pathogenesis and molecular classification of nonfunctional pituitary adenomas, and suggest that therapeutic targeting of the Notch pathway could be effective for these tumors.
NDRG1 overexpression promotes the progression of esophageal squamous cell carcinoma through modulating Wnt signaling pathway
CANCER BIOLOGY & THERAPY
Authors: Ai, Runna; Sun, Yulin; Guo, Zhimin; Wei, Wei; Zhou, Lanping; Liu, Fang; Hendricks, Denver T.; Xu, Yang; Zhao, Xiaohang
Abstract
N-myc down-regulated gene 1 (NDRG1) has been shown to regulate tumor growth and metastasis in various malignant tumors and also to be dysregulated in esophageal squamous cell carcinoma (ESCC). Here, we show that NDRG1 overexpression (91.9%, 79/86) in ESCC tumor tissues is associated with poor overall survival of esophageal cancer patients. When placed in stable transfectants of the KYSE 30 ESCC cell line generated by lentiviral transduction with the ectopic overexpression of NDRG1, the expression of transducin-like enhancer of Split 2 (TLE2) was decreased sharply, however-catenin was increased. Mechanistically, NDRG1 physically associates with TLE2 and -catenin to affect the Wnt pathway. RNA interference and TLE2 overexpression studies demonstrate that NDRG1 fails to active Wnt pathway compared with isogenic wild-type controls. Strikingly, NDRG1 overexpression induces the epithelial mesenchymal transition (EMT) through activating the Wnt signaling pathway in ESCC cells, decreased the expression of E-cadherin and enhanced the expression of Snail. Our study elucidates a mechanism of NDRG1-regulated Wnt pathway activation and EMT via affecting TLE2 and-catenin expression in esophageal cancer cells. This indicates a pro-oncogenic role for NDRG1 in esophageal cancer cells whereby it modulates tumor progression.