Zhenye Li

Integrative proteomics and transcriptomics revealed that activation of the IL-6R/JAK2/STAT3/MMP9 signaling pathway is correlated with invasion of pituitary null cell adenomas

Non-functioning pituitary adenomas (NFPAs) are a highly heterogeneous group, but few studies have explored the invasion mechanism of specific subtypes of NFPAs. The objective of this study was to investigate the differential molecular expression patterns and the critical biological signaling pathways involved in the invasion of pituitary null cell adenomas (PNCAs) through integrative proteomics and transcriptomics. A total of 1160 genes and 283 proteins were found to be differentially expressed in invasive and non-invasive PNCAs. The differentially expressed molecules related to invasion were enriched in 15 canonical signaling pathways, 15 clusters of diseases or biological functions and 5 upstream molecules. Among them, the majority of the differentially expressed molecules were found to be involved in transport of molecule, migration of cells and cell movement. Notably, IL-6 was a significantly activated upstream regulator, and the IL6R/JAK2/STAT3 cascade was found to play a critical role in acute phase response signaling, which was the most significant canonical signaling pathway. Furthermore, we validated the overexpression of IL-6R, JAK2, STAT3, p-STAT3 and MMP9 in invasive PNCAs. Our data suggest that overactivation of the IL-6R/JAK2/STAT3/MMP9 pathway is critical for the invasion of PNCAs.

The role of TGF-β/Smad signaling in dopamine agonist-resistant prolactinomas.

BACKGROUND Prolactinomas are the most common secretory pituitary adenomas. The first line of treatment involves dopamine agonists (DAs); however, a subset of patients is resistant to such therapy. Recent studies suggest that dopamine can up-regulate TGF-β1 synthesis in rat pituitary lactotrophs whereas estradiol down-regulates TGF-β1. To date, the role of TGF-β/Smad signaling in DAs-resistant prolactinomas has not been explored. METHODS High-content screening (HCS) techniques, qRT-PCR, Western blot, immunofluorescence and ELISA, were performed to determine the role of TGF-β/Smad signaling in DAs-resistant prolactinomas. RESULTS We reported a significant down-regulation of TGF-β/Smad signaling cascade in DAs-resistant prolactinomas compared to normal human anterior pituitaries. Following treatment with TGF-β1, the dopamine agonist, bromocriptine, and the estrogen antagonist (ER), fulvestrant in GH3 cells, we found that TGF-β1 and fulvestrant caused significant cytotoxicity in a dose- and time-dependent manner and activated Smad3 was detected following exposure to TGF-β1 and fulvestrant. In addition, treating GH3 cells with fulvestrant increased active TGF-β1 levels and decreased PRL levels in a dose-dependent manner. CONCLUSION TGF-β/Smad signaling pathway may play an important role in DA-resistant prolactinomas and has the potential to be a viable target for the diagnosis and treatment of prolactinomas, particularly in patients who are resistant to DAs.

Overexpression of the cell adhesion molecule claudin-9 is associated with invasion in pituitary oncocytomas

Pituitary oncocytoma is a subtype of nonfunctioning pituitary adenomas with the potential to be locally invasive. Currently, surgery is the most effective treatment, whereas functional pituitary adenomas can be treated by drugs. We analyzed the invasiveness of pituitary oncocytomas to identify biomarkers that may be useful for guiding future therapeutic decision making. To identify important biomarkers of pituitary oncocytomas, 20 oncocytomas that were negative for hormone-specific immunostaining were confirmed by anti-mitochondria antibody immunostaining and electron microscopy. Our clinical phenotype data showed a prominent male predilection (85%). These tumors were classified as invasive or noninvasive based on preoperative magnetic resonance imaging, intraoperative records, and pathology slide. We observed significantly different expression profiles between pituitary oncocytomas (n = 3) and normal pituitary glands (n = 3). A total of 1937 genes were differentially expressed between the pituitary oncocytomas and normal pituitary glands. Among these 1937 genes, 954 were up-regulated and 983 were down-regulated in pituitary oncocytomas. The most significantly altered gene, claudin-9 (CLDN9), was further confirmed by quantitative real-time polymerase chain reaction, Western blot, and immunohistochemical staining in 10 invasive pituitary oncocytoma samples and 10 noninvasive pituitary oncocytoma samples. High levels of CLDN9 were found in the pituitary oncocytomas, whereas low levels were detected in normal pituitary glands. In addition, the CLDN9 expression level was higher in invasive oncocytomas compared with noninvasive oncocytomas. Bioinformatics Gene Ontology analysis was performed to better understand the critical role of CLDN9 in the development and progression of oncocytomas. Consequently, CLDN9 may be an important biomarker for invasive pituitary oncocytomas.

Smad3 and phospho-Smad3 are potential markers of invasive nonfunctioning pituitary adenomas.

Background Transforming growth factor-β (TGF-β) signaling plays important roles in tumor development. Nevertheless, the roles of TGF-β/Smad signaling in nonfunctioning pituitary adenomas (NFPAs) have not been fully studied. Methods Tumor samples were obtained from patients who had NFPAs and underwent endoscopic transsphenoidal surgery or craniotomy at Beijing Tiantan Hospital from March 2008 to December 2012. Immunohistochemistry was performed to determine the expression of Smad transducer proteins in NFPAs. Ki-67 was evaluated as an indicator of the proliferative activity of NFPAs. Results A total of 161 patients with NFPAs were identified; 59 (36.6%) had invasive NFPAs and 102 (63.4%) had noninvasive NFPAs. Protein levels of Smad3 and phospho-Smad3 (p-Smad3) were significantly lower in patients with invasive NFPAs than in patients with noninvasive NFPAs (P<0.05 and P<0.01, respectively). The Ki-67 index was markedly greater in invasive NFPAs than in noninvasive NFPAs (P<0.05) and was significant correlated with p-Smad3 levels (P<0.05, r=−0.702). Conclusion A low level of Smad3 and p-Smad3 proteins was associated with the invasion of NFPAs.

Assessment of sFRP4 as a bio-marker for predicting aggressiveness and recurrence of growth hormone-secreting pituitary adenomas

The association of sFRP4 expression with aggressiveness and recurrence of growth hormone (GH)-secreting pituitary adenomas was investigated. Ten normal pituitary and 52 GH-secreting pituitary adenoma specimens were classified into three groups: normal pituitary (control) group, non-aggressive group, and aggressive group, according to preoperative evaluation by magnetic resonance imaging (MRI)/computed tomography (CT). Expression of sFRP4 was determined by quantitative real-time polymerase chain reaction (qRT-PCR), western blot analysis, and tissue microarrays, to assess the association between sFRP4 and aggressiveness. Follow-up information of all 52 patients was collected to evaluate the impact of sFRP4 expression on the recurrence/progression of GH-secreting pituitary adenomas. qRT-PCR results showed a lower level of sFRP4 mRNA in the aggressive group, as compared to that in the non-aggressive group (P=0.001). A similar trend was observed on western blot analysis for sFRP4 protein expression (P=0.004). On analysis by tissue microarrays, weak sFRP4 expression was detected in the aggressive group (10/15, 66.7%). Univariate analysis showed a significant relationship between low sFRP4 expression and aggressiveness (P=0.024). On multivariate analysis weak sFRP4 expression was found to be an independent factor of recurrence/progression (odds ratio: 0.063, P=0.026). Methylation of the sFRP4 promoter was increased in low sFRP4 staining group compared to that in the high sFRP4 staining group (P<0.001). In this study, weak sFRP4 expression appeared to predict aggressive behavior, and was associated with recurrence/progression of GH-secreting pituitary adenomas. Methylation of the sFRP4 promoter may account for the low sFRP4 expression.

Genome-wide analysis of differentially expressed lncRNAs and mRNAs in primary gonadotrophin adenomas by RNA-seq

Recently, long non-coding RNAs (lncRNAs) have received increased research interest owing to their participation via distinct mechanisms in the biological processes of nonfunctional pituitary adenomas. However, changes in the expression of lncRNAs in gonadotrophin adenoma, which is the most common nonfunctional pituitary adenomas, have not yet been reported. In this study, we performed a genome-wide analysis of lncRNAs and mRNAs obtained from gonadotrophin adenoma patients’ samples and normal pituitary tissues using RNA-seq. The differentially expressed lncRNAs and mRNAs were identified using fold-change filtering. We identified 839 lncRNAs and 1015 mRNAs as differentially expressed. Gene Ontology analysis indicated that the biological functions of differentially expressed mRNAs were related to transcription regulator activity and basic metabolic processes. Ingenuity Pathway Analysis was performed to identify 64 canonical pathways that were significantly enriched in the tumor samples. Furthermore, to investigate the potential regulatory roles of the differentially expressed lncRNAs on the mRNAs, we constructed general co-expression networks for 100 coding and 577 non-coding genes that showed significantly correlated expression patterns in tumor cohort. In particular, we built a special sub-network of co-expression involving 186 lncRNAs interacting with 15 key coding genes of the mTOR pathway, which might promote the pathogenesis of gonadotrophin tumor. This is the first study to explore the patterns of genome-wide lncRNAs expression and co-expression with mRNAs, which might contribute to the molecular pathogenesis of gonadotrophin adenoma.

Phosphorylation of kinase insert domain receptor by cyclin-dependent kinase 5 at serine 229 is associated with invasive behavior and poor prognosis in prolactin pituitary adenomas

Pituitary adenomas constitute 15-20% of intracranial neoplasms. Previously we reported that cyclin-dependent kinase 5 (CDK5) is upregulated in pituitary tumors associated with activating protein p35, and plays an essential role in pituitary adenomas progression. Here we explored the mechanisms of CDK5 signaling in prolactin pituitary adenomas. Our data indicate that p35 expression and CDK5 activity are both significantly increased in human invasive prolactin pituitary adenomas as compared to noninvasive forms of pituitary adenomas. Inhibition of CDK5 activity suppressed cell migration and invasive ability in GH3 rat pituitary cells. We identified that CDK5 phosphorylates serine 229 residue (Ser-229) of kinase insert domain receptor (KDR), also known as VEGFR-2, in prolactin pituitary adenomas. Phosphorylation of Ser-229 is required for proper KDR surface localization. Phosphorylated Ser-229 in KDR (pSer-229) levels are significantly higher in noninvasive and invasive prolactin pituitary adenomas compared to normal pituitary tissues. In addition, our data indicated that higher KDR pSer-229 correlates with worse prognosis in patients with prolactin pituitary adenomas. In summary, our results illustrated that CDK5-mediated KDR phosphorylation controls prolactin pituitary adenoma progression and KDR pSer-229 serves as a potential prognostic biomarker for both noninvasive and invasive pituitary adenomas.

Epithelial–Mesenchymal Transition Induced by SMAD4 Activation in Invasive Growth Hormone-Secreting Adenomas

Abstract Background The detection and treatment of invasive growth hormone-secreting pituitary adenoma (GHPA) remains challenging. Several transcription factors promoting the epithelial–mesenchymal transition (EMT) can act as cofactors for the transforming growth factor-beta (TGF-ß)/SMAD4. The goal of this study was to investigate the association of SMAD4 expression and clinicopathologic features using a tissue microarray analysis (TMA). The levels of SMAD4 and the related genes of EMT in GHPAs were analyzed by q-PCR and western blot. SMAD4 was strongly expressed in 15/19 cases (78.9%) of invasive GHPA and 10/42 cases (23.8%) of noninvasive GHPA (χ2=10.887, p=0.000). In the high SMAD4 group, a headache was reported in 16/25 cases (64%) compared with 13/36 cases (36.1%) in the low SMAD4 group (χ2=4.565, p=0.032). The progression-free survival (PFS) in the high group was lower than that in the low group (p=0.026). qRT-PCR and western blot analysis further revealed a significant downregulation of E-cadherin and upregulation of N-cadherin and vimentin in the invasive GHPA group. SMAD4 was associated with increased levels of invasion of GH3 cells, as determined by a transwell test. SMAD4 downregulated E-cadherin levels and increased the levels of N-cadherin and vimentin. Our data provide evidence that SMAD4 is a potential prognosis biomarker and a therapeutic target for patients with invasive GHPA.

Pure Endoscopic Treatment of Middle-Fossa Arachnoid Cyst With Rupture: Report of 2 Cases and Literature Review

Rupture of arachnoid cysts is extremely rare. We herein report 2 cases of ruptured middle-fossa cysts with endoscopic treatment and review 30 previously published cases. Two pediatric male patients had a middle-fossa cyst accompanied by ipsilateral subdural effusion. Both patients had a tear in the outer membrane of the cyst detected by endoscopy. The tear was enlarged and fenestration of the medial wall was performed under endoscopy. Short-term postoperative imaging showed no obvious remission of the cyst or subdural effusion, and both patients had a satisfactory outcome in the short-term follow-up. The literature review revealed that middle-fossa arachnoid cysts were the most frequent type of cyst among the 30 cases, and 22 of all 27 middle-fossa arachnoid cysts were Galassi types II and III. We believe that large-volume middle-fossa arachnoid cysts tend to rupture secondary to an increase in pressure within the cyst caused by trauma and other factors that increase the intracranial pressure. Endoscopy is an effective and minimally invasive method for ruptured middle-fossa arachnoid cysts accompanied by subdural effusion. We advocate adequate communication among the cyst, subdural space, and cistern to achieve the best outcome.