Xianrui Yuan

miR-25 promotes glioblastoma cell proliferation and invasion by directly targeting NEFL

Glioblastoma multiforme (GBM) is the most malignant and common brain tumor; it is aggressive growth pattern means that GBM patients face a poor prognosis even when receiving the best available treatment modalities. In recent years, an increasing number of reports suggest that the discovery of microRNAs (miRNAs) might provide a novel therapeutic target for human cancers, including GBM. One miRNA in particular, microRNA-25 (miR-25), is overexpressed in several cancers, wherein accumulating evidence indicates that it functions as an oncogene. However, the function of miR-25 in GBM has not been totally elucidated. In this study, we demonstrated that miR-25 was significantly up-regulated in astrocytoma tissues and glioblastoma cell lines. In vitro studies further demonstrated that overexpressed miR-25 was able to promote, while its antisense oligos inhibited cell proliferation and invasion in U251 cells. Moreover, we identified neurofilament light polypeptide (NEFL) as a novel target molecule of miR-25. Also of note was the fact that NEFL was down-regulated with increased levels of miR-25 expression in human astrocytoma clinical specimens. In addition, via the mTOR signaling pathway, NEFL-siRNA could significantly attenuate the inhibitory effects of knockdown miR-25 on the proliferation and invasion of U251 cells. Overall, our results showed an important role for miR-25 in regulating NEFL expression in GBM, and suggest that miR-25 could be a potential target for GBM treatment.

PTK7 regulates Id1 expression in CD44-high glioma cells

BACKGROUND CD44 is a molecular marker associated with molecular subtype and treatment resistance in glioma. More effective therapies will result from approaches aimed at targeting the CD44-high gliomas. METHODS Protein tyrosine kinase 7 (PTK7) mRNA expression was analyzed based on The Cancer Genome Atlas glioblastoma dataset. PTK7 expression was depleted through lentivirus-mediated short hairpin RNA knockdown. Terminal deoxynucleotidyl transferase dUTP nick-end labeling was used to evaluate cell apoptosis following PTK7 knockdown. Gene expression analysis was performed on Affymetrix microarray. A nude mice orthotopic tumor model was used to evaluate the in vivo effect of PTK7 depletion. RESULTS PTK7 is highly expressed in CD44-high glioblastoma and predicts unfavorable prognosis. PTK7 knockdown attenuated cell proliferation, impaired tumorigenic potential, and induced apoptosis in CD44-high glioma cell lines. Gene expression analysis identified inhibitor of DNA Binding 1 (Id1) gene as a potential downstream effector for PTK7. Overexpression of Id1 mostly restored the cell proliferation and colony formation attenuated by PTK7 depletion. PTK7 enhanced anchorage-independent growth in normal human astrocytes, which was attenuated by Id1 knockdown. Furthermore, PTK7 regulated Id1 expression through modulating TGF-β/Smad signaling, while pharmacological inhibition on TGF-β/Smad signaling or PTK7/Id1 depletion attenuated TGF-β-stimulated cell proliferation. PTK7 depletion consistently reduced Id1 expression, suppressed tumor growth, and induced apoptosis in a murine orthotopic tumor model, which could be translated into prolonged survival in tumor-bearing mice. CONCLUSIONS PTK7 regulates Id1 expression in CD44-high glioma cell lines. Targeting PTK7 could be an effective strategy for treating glioma with high CD44 expression.

HESRG: a novel biomarker for intracranial germinoma and embryonal carcinoma

The novel stem cell-related gene, HESRG, was first identified by our group, and its expression pattern in human tumors remains unknown. In this study, we used RT-PCR to systematically investigate the expression of HESRG in various types of intracranial tumors and found that HESRG was expressed only in germinoma and embryonal carcinoma, but hardly at all in other types of brain tumors. Real-time PCR results further confirmed this expression pattern. Subsequently, we tested 134 intracranial non-germ cell tumors and 64 intracranial germ cell tumors by immunohistochemistry. Our results showed that HESRG was expressed strongly and diffusively in the nuclei of tumor cells in intracranial germinoma and embryonal carcinoma as well as in human embryonic stem cells. No positive staining signal was observed in any other type of intracranial tumors. In germinomas, 25 of 31 showed intensive (3+) expression, four cases showed moderate (2+) immunostaining and the remaining 2 cases showed weak (1+) immunostaining. In embryonal carcinoma, 6 of 9 showed intensive (3+) immunostaining and 3 of 9 showed moderate (2+) immunostaining. These results suggest that HESRG is a novel, sensitive and specific biomarker for intracranial germinoma and embryonal carcinoma.

ALDH1 expression is correlated with pathologic grade and poor clinical outcome in patients with astrocytoma.

Aldehyde dehydrogenase 1 (ALDH1), a detoxifying enzyme, is a stem-like cell marker, but its expression pattern and clinical significance in astrocytoma remain unclear. In this study, we used immunohistochemical analysis to systematically investigate the expression of ALDH1 in 76 astrocytomas of different pathological grade and seven samples of normal brain tissues. We found that ALDH1 was expressed in some of the astrocytomas but was not detected in normal brain tissues. The proportion of ALDH1-expressing cells was positively correlated with the pathological grade of the astrocytomas, but not with patient age, sex or tumor size. We also collected detailed follow-up data and analyzed the correlation of ALDH1 expression with overall survival (OS) and progression-free survival (PFS) using univariate and multivariate analysis. We found that the proportion of ALDH1-positive cells was an independent prognostic factor for PFS and OS. These results show that ALDH1 is expressed in astrocytoma, and that its expression is correlated with pathological grade and patient survival.

Microsurgical Management of Craniopharyngiomas via a Unilateral Subfrontal Approach: A Retrospective Study of 177 Continuous Cases

OBJECTIVE To evaluate the outcomes of 177 cases of craniopharyngioma (CP) treated via a unilateral subfrontal approach. METHODS A total of 177 continuous microscopic surgeries were performed by the senior author (Y.X.). The tumors were divided into 6 groups using the diaphragm sellae and the third ventricle floor as the anatomic references. The preoperative, postoperative, and long-term follow-up data were analyzed to evaluate the extent of tumor resection, recurrence, and functional status. RESULTS The subfrontal-basal approach was used in 169 (91.4%) cases. Total resection was achieved in 167 (94.4%) cases. A total of 158 patients were followed from 6 to 130 months. There were 3 perioperative and 23 delayed deaths. Twenty-two patients had tumor recurrence (12.7%). The progression-free survival was 80% at 5 years and 72% at 10 years. The overall survival was 84.0% at 2.5 years and 83.2% at 10 years. There was a significant increase of pituitary dysfunction after total resection. Neurologic function was stable in most patients. Rate of hypothalamic dysfunction and mortality were higher in patients with intraventricular CPs. Of the surviving patients, 91.8% were living independently with acceptable morbidities at the end of the study. CONCLUSIONS Most CPs extend along the intrasellar-suprasellar-third ventricle axis. A subfrontal-basal approach is a simple, safe, and effective approach to resecting CPs extending along the vertical axis. A translamina terminalis approach is an ideal corridor to resect intraventricular CP. The benefit of radical resection remains controversial, especially for CPs involving the infundibulotuberal region.

Pituitary stalk management during the microsurgery of craniopharyngiomas

In the present study, 203 patients that had previously undergone microsurgery for craniopharyngiomas (CPs) between 1992 and 2012 were analyzed retrospectively on a long-term follow-up basis to investigate the differences in the recurrence rate and endocrine function between patients with preserved and resected pituitary stalks. To summarize the possible outcomes of microsurgery, the 203 patients were divided into 2 groups: Group A that had preserved pituitary stalks and Group B that had undergone resections of the pituitary stalk. Tumor origins and the involvement of the pituitary stalk during surgery were observed. From 2010 onwards, an ultra-electron microscope was used postoperatively to detect whether pituitary stalk specimens were infiltrated or invaded with tumor cells. Long-term follow-up observations of the patients included tumor recurrence, postoperative endocrine dysfunction and visual acuity and field. Among the 203 patients, 175 patients received gross-total resection (GTR) (175/203, 86.2%), 28 patients underwent subtotal resection (28/203, 13.8%) and 34 patients had surgery that preserved the pituitary stalk (34/203, 16.7%). There was no significant difference in the recurrence rate between Group A (4/34, 11.8%) and the patients in Group B (10/123, 8.1%) who underwent GTR and also received follow-ups. Of the 157 patients who were followed up, 91 individuals underwent endocrine evaluation and the outcome was divided into normal, satisfactory and poor grades. The results for Group A were 5, 18 and 0, respectively, while the results for Group B were 1, 60 and 7, respectively, which showed a statistically significant difference between the groups. Pituitary stalk specimens of 15 patients were studied postoperatively using an ultra-electron microscope and all samples showed tumor cells had invaded the pituitary stalk (15/15, 100%). Total resections of CPs with the pituitary stalk were recommended if the pituitary stalk was intraoperatively invaded. In cases where the pituitary stalk was not involved, microsurgical excisions preserving the pituitary stalk were preferred, as there was no significant increase in the recurrence rate and the patients experienced less endocrine dysfunction.

The expression of moesin in astrocytoma: correlation with pathologic grade and poor clinical outcome

Moesin, a member of the ERM family, acts as a linker between the actin cytoskeleton and the plasma membrane and plays a key role in the control of cell morphology, motility, adhesion and other processes of tumourigenesis. The expression pattern and clinical significance of moesin in astrocytoma remain unknown. In this study, we used RT-PCR to systematically investigate the expression of moesin in 49 astrocytomas of different pathological grade and 6 normal brain tissues. We found that the mRNA expression levels of moesin in astrocytomas were significantly higher in comparison with normal brain tissues. Furthermore, moesin up-regulation was correlated with pathological grade of astrocytomas. Subsequently, we tested 112 astrocytomas and 14 normal brain tissues by immunohistochemistry. Similar results were also confirmed. Univariate and multivariate survival analysis were used to determine the correlations of moesin expression with overall survival and progression-free survival. Our results showed the expression of moesin was strongly negatively correlated with the patient progression-free survival and overall survival. These results suggest moesin protein involved in the genesis and progression of astrocytomas and might be regarded as an independent predictor of poor prognosis.

Intramedullary thoracic spinal cord meningioma: a rare case report and review of the literature.

A 33-year-old male presented with a thoracic spinal intramedullary meningioma manifesting as bilateral asymmetric progressive weakness in the lower extremities. Preoperative magnetic resonance imaging (MRI) showed an intramedullary mass at the T1-T3 level. Intraoperative inspection found that the spinal cord was markedly swollen with a normal surface while dural attachment was not confirmed. Gross total removal of the tumor was achieved. The morphologic and immunohistochemical findings were compatible with the diagnosis of meningioma. Postoperatively, the patient recovered from preoperative paraplegia. Although extremely rare, meningiomas should be considered when diagnosing intramedullary tumors.

Ectopic recurrence of pediatric craniopharyngiomas after gross total resection: a report of two cases and a review of the literature

IntroductionEctopic recurrent craniopharyngioma is rare. We reported two pediatric cases and reviewed the related literature.MethodWe retrospectively studied 177 craniopharyngioma cases treated by the senior author (Yuan X) between years 2003 and 2013. Two ectopic recurrent craniopharyngiomas were identified. One was discovered under the right frontal lobe and the other was found in the fourth ventricle. Both patients underwent a second radical resection without complications. Then we conducted an extensive review of peer-reviewed, English-language literatures in the US National Library of Medicine, focusing on the treatment modalities, recurrent sites, and clinical outcomes.ResultsSixty ectopic recurrent tumors have been reported so far (including this study). Thirty-three tumors were located in the previous surgical corridors and 27 were disseminated along the cerebrospinal fluid pathway. All recurrent tumors were surgically removed. The gross total resection (GTR) rates were 87 and 63 %, respectively.ConclusionThe natural course of recurrent ectopic craniopharyngiomas is progressive. GTR is the treatment of choice. Regular follow-ups are strongly recommended to detect any further recurrence.

Inhibition of Rb and mTOR signaling associates with synergistic anticancer effect of palbociclib and erlotinib in glioblastoma cells

SummaryGenomic studies have established a set of three core-signaling pathways, receptor tyrosine kinase (RTK), p53 and retinoblastoma (Rb) signaling pathways, contributing glioblastoma (GBM) and revealed that dysregulation of at least two pathways is required for GBM progression. In the present study, we investigate efficacy of combination of palbociclib, cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, and erlotinib, epidermal growth factor receptor (EGFR) inhibitor in GBM cell systems with different p53 status. Cell proliferation and colony formation assays showed that the combination treatment synergistically suppressed GBM cell proliferation. LN229 cells with mutant p53 and wild-type PTEN were more sensitive to the combination treatment. Further studies indicated that the synergetic anti-GBM effects were due to cell apoptosis induction and cell cycle arrest at G1 phase. Signaling examination indicated that levels of p-Rb and p-4E-BP1 significantly decreased by the combination treatment; however, Akt and MAPK signaling were differentially suppressed among the three GBM cell lines. Hence, our data demonstrate that palbociclib and erlotinib exert synergistic anti-GBM activity, providing pre-clinical evidence and a proof-ofconcept that usage of the combination of EGFR and CDK4/6 inhibitors for GBM treatment.