Human WIF1 peptide

The etiology of sporadic pituitary tumors is currently unknown. The Writ pathways have been implicated in the pathogenesis of a variety of human tumors, but the role of these pathways in pituitary tumors is unclear. Microarray analysis using the Affymetrix HG U133 plus 2.0 GeneChips identified four secreted frizzled-related protein (sFRP) family members of Writ pathway inhibitors that were differentially expressed in both nonfunctioning and clinically functioning pituitary tumors (n = 20) compared with normal pituitary controls (n = 3). Reduced tumor expression of Writ inhibitory factor-1 (WIF1), sFRP2, and sFRP4 mRNA was confirmed by real-time quantitative RT-PCR (P < 0.001 and P = 0.002 and 0.013, respectively) in all pituitary subtypes. Hypermethylation of the WIF1 promoter was present in 88% of the pituitary tumors (n = 41). Seventy-six percent of pituitary tumors demonstrated absent or weak cytoplasmic WIF1 staining by immunohistochemistry (n = 41), although preserved staining was seen in some functioning tumors, with strong staining in 92% of normal pituitary controls (n = 13). The Writ pathway target gene cyclin D1 was found to be up-regulated specifically in the nonfunctioning pituitary tumors compared with controls at,; both mRNA and protein level, supportive of activation of the Wnt-beta-catenin pathway. Nuclear accumulation of P-catenin, however, was not observed in any pituitary tumors (n = 70). By transfecting GH3 cells with WIF1, decreased,cell proliferation and colony formation was observed compared with empty vector controls. In conclusion, our data suggest that WIF1 may be a tumor suppressor, specifically in nonfunctioning pituitary tumors, and that the Writ pathways are important in pituitary tumorigenesis.

The present study aimed to investigate the expression of long non-coding HOX transcript antisense RNA (lncRNA-HOTAIR) in the serum of patients with lymph node metastasis of papillary thyroid carcinoma (PTC) and the underlying mechanism. A total of 89 patients with PTC at Beijing Geriatric Hospital were recruited in this study. Based on the results of color Doppler ultrasound examination, the patients were evaluated for cervical lymph node metastases, and were thereby divided into a metastasis-negative group and a metastasis-positive group. Quantitative fluorescent PCR was used to assess the expression of HOTAIR in serum samples. The PTC cell line TPC-1 was randomly divided into a control and siRNA group. The control group was transfected with a nonsense sequence, while the siRNA group was transfected with si-HOTAIR. After transfection, cell proliferation was evaluated using the MTT assay, and cell migration and invasion were assessed using the cell scratch assay and Transwell assay. Expression levels of vimentin, E-cadherin and proteins associated with the Wnt/beta-catenin signaling pathway were assessed using western blot analysis. Based on the results of the ultrasound examination, 53 patients were allocated to the metastasis-negative group, and 36 to the metastasis-positive group. The expression level of lncRNA-HOTAIR was higher in the metastasis-positive group than that in the metastasis-negative group (P<0.05). Compared with the control group, cell proliferation was reduced while cell migration rate and the number of migrating cells were increased in the siRNA group. Compared with the control group, the expression levels of WIF1 and E-cadherin were significantly increased, while the levels of beta-catenin and vimentin were significantly decreased. In conclusion, lncRNA-HOTAIR is overexpressed in the serum of patients with lymph node metastasis of PTC.In vitroexperiments showed that HOTAIR promoted the proliferation and metastasis of PTC cells by regulating epithelial-mesenchymal transition (EMT) mediated by the Wnt/catenin pathway. Thus, lncRNA-HOTAIR is proposed as a molecular target for the treatment of lymph node metastasis of PTC.