Jiwei Bai

Lower PRDM2 expression is associated with dopamine-agonist resistance and tumor recurrence in prolactinomas.

BackgroundDopamine agonists (DAs) are the first-line treatment for prolactinomas, which account for 25–30% of functioning pituitary adenomas, and bromocriptine (BRC) is the only commercially available DAs in China. However, tumors are resistant to therapy in 5–18% of patients.MethodsThe exomes of six responsive prolactinomas and six resistant prolactinomas were analyzed by whole-exome sequencing.ResultsUsing stringent variant calling and filtering parameters, ten somatic variants that were mainly associated with DNA repair or protein metabolic processes were identified. New resistant variants were identified in multiple genes including PRDM2, PRG4, MUC4, DSPP, DPCR1, RP1L1, MX2, POTEF, C1orf170, and KRTAP10-3. The expression of these genes was then quantified by real-time reverse-transcription PCR (RT–qPCR) in 12 prolactinomas and 3 normal pituitary glands. The mRNA levels of PRDM2 were approximately five-fold lower in resistant prolactinomas than in responsive tumors (p < 0.05). PRDM2 protein levels were lower in resistant prolactinomas than in responsive tumors, as determined by Western blotting and immunohistochemical analysis (p < 0.05). Overexpression of PRDM2 upregulated dopamine receptor D2 (D2DR) and inhibited the phosphorylation of ERK1/2 in MMQ cells. PRDM2 showed a synergistic effect with BRC on the inhibition of prolactin (PRL) secretion and MMQ cell viability, and low PRDM2 expression was associated with tumor recurrence.ConclusionsPRDM2 downregulation may play a role in dopamine-agonist resistance and tumor recurrence in prolactinomas.

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.

Identification of Differentially Expressed Genes in Pituitary Adenomas by Integrating Analysis of Microarray Data

Pituitary adenomas, monoclonal in origin, are the most common intracranial neoplasms. Altered gene expression as well as somatic mutations is detected frequently in pituitary adenomas. The purpose of this study was to detect differentially expressed genes (DEGs) and biological processes during tumor formation of pituitary adenomas. We performed an integrated analysis of publicly available GEO datasets of pituitary adenomas to identify DEGs between pituitary adenomas and normal control (NC) tissues. Gene function analysis including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) networks analysis was conducted to interpret the biological role of those DEGs. In this study we detected 3994 DEGs (2043 upregulated and 1951 downregulated) in pituitary adenoma through an integrated analysis of 5 different microarray datasets. Gene function analysis revealed that the functions of those DEGs were highly correlated with the development of pituitary adenoma. This integrated analysis of microarray data identified some genes and pathways associated with pituitary adenoma, which may help to understand the pathology underlying pituitary adenoma and contribute to the successful identification of therapeutic targets for pituitary adenoma.

Whole‑exome sequencing identifies variants in invasive pituitary adenomas

Pituitary adenomas exhibit a wide range of behaviors. The prediction of invasion or malignant behavior in pituitary adenomas remains challenging. The objective of the present study was to identify the genetic abnormalities associated with invasion in sporadic pituitary adenomas. In the present study, the exomes of six invasive pituitary adenomas (IPA) and six non-invasive pituitary adenomas (nIPA) were sequenced by whole-exome sequencing. Variants were confirmed by dideoxynucleotide sequencing, and candidate driver genes were assessed in an additional 28 pituitary adenomas. A total of 15 identified variants were mainly associated with angiogenesis, metabolism, cell cycle phase, cellular component organization, cytoskeleton and biogenesis immune at a cellular level, including 13 variants that occurred as single nucleotide variants and 2 that comprised of insertions. The messenger RNA (mRNA) levels of diffuse panbronchiolitis critical region 1 (DPCR1), KIAA0226, myxovirus (influenza virus) resistance, proline-rich protein BstNI subfamily 3, PR domain containing 2, with ZNF domain, RIZ1 (PRDM2), PR domain containing 8 (PRDM8), SPANX family member N2 (SPANXN2), TRIO and F-actin binding protein and zinc finger protein 717 in IPA specimens were 50% decreased compared with nIPA specimens. In particular, DPCR1, PRDM2, PRDM8 and SPANXN2 mRNA levels in IPA specimens were approximately four-fold lower compared with nIPA specimens (P=0.003, 0.007, 0.009 and 0.004, respectively). By contrast, the mRNA levels of dentin sialophospho protein, EGF like domain, multiple 7 (EGFL7), low density lipoprotein receptor-related protein 1B and dynein, axonemal, assembly factor 1 (LRRC50) were increased in IPA compared with nIPA specimens (P=0.041, 0.037, 0.022 and 0.013, respectively). Furthermore, decreased PRDM2 expression was associated with tumor recurrence. The findings of the present study indicate that DPCR1, EGFL7, the PRDM family and LRRC50 in pituitary adenomas are modifiers of tumorigenesis, and most likely contribute to the development of oncocytic change and to the invasive tumor phenotype.

Endoscopic treatment of suprasellar cysts without hydrocephalus.

OBJECTIVE At present, endoscopic treatment is advised as the first procedure in cases of suprasellar arachnoid cysts (SSCs) with hydrocephalus. However, the appropriate therapy for SSCs without hydrocephalus has not been fully determined yet because such cases are very rare and because it is usually difficult to perform the neuroendoscopic procedure in patients without ventriculomegaly given difficulties with ventricular cannulation and the narrow foramen of Monro. The purpose of this study was to find out the value of navigation-guided neuroendoscopic ventriculocystocisternostomy (VCC) for SSCs without lateral ventriculomegaly. METHODS Five consecutive patients with SSC without hydrocephalus were surgically treated using endoscopic fenestration (VCC) guided by navigation between March 2014 and November 2015. The surgical technique, success rate, and patient outcomes were assessed and compared with those from hydrocephalic patients managed in a similar fashion. RESULTS The small ventricles were successfully cannulated using navigational tracking, and the VCC was accomplished in all patients. There were no operative complications related to the endoscopic procedure. In all patients the SSC decreased in size and symptoms improved postoperatively (mean follow-up 10.4 months). CONCLUSIONS Endoscopic VCC can be performed as an effective, safe, and simple treatment option by using intraoperative image-based neuronavigation in SSC patients without hydrocephalus. The image-guided neuroendoscopic procedure improved the accuracy of the endoscopic approach and minimized brain trauma. The absence of hydrocephalus in patients with SSC may not be a contraindication to endoscopic treatment.

Upregulation of cyclin B1 plays potential roles in the invasiveness of pituitary adenomas

Predicting aggressive or malignant behavior of pituitary adenomas (PAs) remains challenging. Aberrant expression of cyclin B1 (CCNB1) occurred in various tumors including PAs. Our study was aimed to explore its roles in the development of PAs aggressiveness. According to the integrated analysis, the expression of CCNB1 was evaluated. Following bioinformatics analysis was performed to uncover the pathways CCNB1 involved in and the upstream transcriptional regulation factors. The mRNA expression of CCNB1 was verified by qRT-PCR. Immunohistochemistry analysis was conducted to examine the expression of CCNB1 protein in three groups of PAs (non-invasive, invasive and aggressive-invasive). In this study, CCNB1 was up-regulated in PAs versus normal pituitary. Functional annotation revealed CCNB1 was mainly involved in p53 signaling pathway and cell cycle, which affected proliferation and contributed to tumorigenesis. The constructed transcriptional regulatory network contained 22 upstream transcriptional factors for CCNB1. Moreover, the network also suggested the interactions between CCNB1 and other genes implicated in proliferation (BUB1, CDC25C and TTK). Immunohistochemistry showed staining of CCNB1 was positive in PAs, and its expression was gradually enhanced with the increased invasiveness. In conclusion, up-regulation of CCNB1, together with other regulatory molecules in cell cycle, may play roles in the PAs pathology and could be an indicator for invasiveness of PAs.

Association of TGF-β1 and WIF1 Expression with 36 Paired Primary/Recurrent Nonfunctioning Pituitary Adenomas: A High-Throughput Tissue Microarrays Immunohistochemical Study

OBJECTIVE This study was undertaken primarily to research transforming growth factor β1 (TGF-β1) and Wnt inhibitory factor 1 (WIF1) for the prediction of nonfunctioning pituitary adenoma (NFPAs) invasion and recurrence of tumor samples and the relations between quantitatively determined markers and clinical characters. METHODS We studied 104 patients, including 59 patients without recurrence and 45 patients with recurrence (9 patients with one surgery and 36 patients operated twice, both tumors being studied). All tissues were immunostained for TGF-β1 and WIF1 using tissue microarrays and confirmed with real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot. RESULTS We found that invasion, TGF-β1, and WIF1 were significantly associated with recurrence and that age was associated with low expression of TGF-β1 and WIF1 (P < 0.001). There were no statistically significant differences in the expression of the 2 proteins between the noninvasive and the invasive groups. The expression of TGF-β1 and WIF1 in primary tumors in the recurrence group was lower than in the nonrecurrence group (P < 0.001). In the 36 paired primary or recurrent tumors, the expression of TGF-β1 and WIF1 in recurrent tumors was higher than the expression of primary tumors, which was confirmed with qRT-PCR and Western blot. Therefore, TGF-β1 and WIF1 seem to be related to recurrence or progression of pituitary adenomas. CONCLUSIONS The expression of TGF-β1 and WIF1 in NFPAs correlated with cell proliferation and recurrence potential. They may be good markers of progressive behavior in NFPAs; however, the biologic mechanism needs further study.

Corrigendum to “Identification of Differentially Expressed Genes in Pituitary Adenomas by Integrating Analysis of Microarray Data”

[This corrects the article DOI: 10.1155/2015/164087.].

In Reply to “Prognostic Significance of Resection Degree in Skull Base Chordoma: A Systematic Review and Meta-Analysis”

The authors did a great job of reviewing the related published articles. They performed a systematic review and found that degree of resection was significantly associated with overall survival (OS) and progression-free survival (PFS). Until now, many studies have reported the association between degree of resection and the patients’ prognosis. Jahangiri et al. reported that total resection would decrease further growth or regrowth. Choy et al. reviewed 57 patients retrospectively and found that extent of resection was not associated with recurrence. Wu et al. reported that degree of resection was correlated significantly with OS and PFS. Boari et al. found that extent of resection was a positive independent predictor of OS, but no correlation was found between PFS and extent of resection.

Use of micro-positron emission tomography with 18 F-fallypride to measure the levels of dopamine receptor-D2 and 18 F-FDG as molecular imaging tracer in the pituitary glands and prolactinomas of Fischer-344 rats

Dopamine receptor-D2 (DRD2) is the most important drug target in prolactinoma. The aim of this current study was to investigate the role of using micro-positron emission tomography (micro-PET) with 18F-fallypride and 18F-fluorodeoxyglucose (18F-FDG) as molecular imaging tracer in the pituitary glands and prolactinomas of Fischer-344 (F344) rats and detect the difference of the levels of DRD2 in the pituitary glands and prolactinomas of F344 rat prolactinoma models. Female F344 rat prolactinoma models were established by subcutaneous administration of 15 mg 17β-estradiol for 8 weeks. The growth of tumors was monitored by the small-animal magnetic resonance imaging and micro-PET. A series of molecular biological experiments were also performed 4 and 6 weeks after pump implantation. The micro-PET molecular imaging with 18F-fallypride revealed a decreased expression of DRD2 in F344 rat prolactinoma models, but the micro-PET molecular imaging with 18F-FDG presented an increased uptake in the prolactinoma compared with the pituitary gland. A decreasing trend of levels of DRD2 in F344 rat prolactinoma models was also detected by molecular biological experiments. From this, we can conclude that micro-PET with 18F-fallypride and 18F-FDG can be used to assess tumorigenesis of the prolactinomas in vivo and molecular imaging detection of DRD2 level in prolactinoma may be an indication of treatment effect in the animal experiment.