RNA-binding protein Musashi1 modulates glioma cell growth through the post-transcriptional regulation of Notch and PI3 kinase/Akt signaling pathways

Musashi1 (MSI1) is an RNA-binding protein that plays critical roles in nervous-system development and stem-cell self-renewal. Here, we examined its role in the progression of glioma. Short hairpin RNA (shRNA)-based MSI1-knock down (KD) in glioblastoma and medulloblastoma cells resulted in a significantly lower number of self renewing colony on day 30 (a 65% reduction), compared with non-silencing shRNA-treated control cells, indicative of an inhibitory effect of MSI1-KD on tumor cell growth and survival. Immunocytochemical staining of the MSI1-KD glioblastoma cells indicated that they ectopically expressed metaphase markers. In addition, a 2.2-fold increase in the number of MSI1-KD cells in the G2/M phase was observed. Thus, MSI1-KD caused the prolongation of mitosis and reduced the cell survival, although the expression of activated Caspase-3 was unaltered. We further showed that MSI1-KD glioblastoma cells xenografted into the brains of NOD/SCID mice formed tumors that were 96.6% smaller, as measured by a bioluminescence imaging system (BLI), than non-KD cells, and the host survival was longer (49.3±6.1 days vs. 33.6±3.6 days; P<0.01). These findings and other cell biological analyses suggested that the reduction of MSI1 in glioma cells prolonged the cell cycle by inducing the accumulation of Cyclin B1. Furthermore, MSI1-KD reduced the activities of the Notch and PI₃ kinase-Akt signaling pathways, through the up-regulation of Numb and PTEN, respectively. Exposure of glioma cells to chemical inhibitors of these pathways reduced the number of spheres and living cells, as did MSI1-KD. These results suggest that MSI1 increases the growth and/or survival of certain types of glioma cells by promoting the activation of both Notch and PI₃ kinase/Akt signaling.

Importance of preserved periosteum around jugular foramen neurinomas for functional outcome of lower cranial nerves: anatomic and clinical studies

BACKGROUND

Surgical removal of jugular foramen (JF) neurinomas remains controversial because of their radicality in relation to periosteal sheath structures.

OBJECTIVE

To clarify the particular meningeal structures of the JF with the aim of helping to eliminate surgical complications of the lower cranial nerves (LCNs).

METHODS

We sectioned 6 JFs and examined histological sections using Masson trichrome stain. A consecutive series of 25 patients with JF neurinomas was also analyzed, and the MIB-1 index of each excised tumor was determined.

RESULTS

In the JF, meningeal dura disappeared at the nerve entrance, forming a jugular pocket. JF neurinomas were classified into 4 types: subarachnoid (type A by the Samii classification), foraminal (type B), epidural (type C), and episubdural (type D). After an average follow-up of 9.2 years, tumors recurred in 9 cases (36%). Type A tumors did not show regrowth, unlike type B tumors, in which all recurred. Radical surgery by the modified Fisch approach did not contribute to tumor radicality in type C and D tumors, even in cases in which LCN function was sacrificed. In preserved periosteum, postoperative LCN deterioration was decreased. Bivariate correlation analysis revealed that jugular pocket extension, tumor removal, MIB-1 greater than 3%, and reoperation or gamma knife use were significant recurrence factors.

CONCLUSION

For LCN preservation, the periosteal layer covering the cranial nerves must be left intact except in patients with a subarachnoid tumor. To prevent tumor regrowth, postoperative gamma knife treatment is recommended in tumors with an MIB-1 greater than 3%.

Long-term outcome of fibrous dysplasia: reconstruction with dysplastic bone--case report

A 10-year-old girl presented with facial asymmetry associated with bulging of the right fronto-orbital region with no symptoms. Computed tomography demonstrated enlargement of the right zygomatic, frontal, ethmoid, and sphenoid bones. Abnormal proliferation of the bone had obliterated the sphenoid, right frontal sinus, and right ethmoid sinuses. These radiological findings suggested right optic nerve compression due to fibrous dysplasia. Right optic canal decompression was performed. In preparation for recurrence, the resulting bone defect in the right orbital roof was reconstructed using the outer table of the split lesion bone. The removed frontal bone was divided into intact and lesioned parts, and the intact part was returned. The lesioned part was split and the outer table graft used to reconstruct the frontal region. A temporal musculopericranial flap was used to form a barrier between the opened ethmoid sinus and cranial cavity. A protrusion appeared on the left forehead 10 years later, and was shaved to improve the aesthetic appearance. The patient was followed up for a total of 23 years. The use of dysplastic bone involves the risk of recurrence, but the period of recurrence is delayed and the progression stops after adolescence, so the second operation involved only shaving for aesthetic appearance. This procedure is one of the treatments of choice because of easy reconstruction, easy revision, and good results.

Malignant brain tumor with rhabdoid features in an adult

Rhabdoid tumor (RT) of the central nervous system is an uncommon and aggressive neoplasm that usually affects pediatric patients. Currently, these tumors are classified as malignant RT or atypical teratoid/RT. Another entity of intraparenchymal brain tumor with a rhabdoid component is the extremely rare rhabdoid glioblastoma. A 23-year-old woman presented with a malignant RT in the right thalamus. The tumor was adjacent to the right lateral ventricle and was partially resected. Histological examination revealed prominent proliferation of rhabdoid cells, which is consistent with a diagnosis of malignant RT; the typical features of glioblastoma were not observed. The tumor cells stained positively for integrase interactor-1 and glial fibrillary acidic protein. Therefore, the tumor may have originated from glial components. Genetic analysis using comparative genomic hybridization showed a deoxyribonucleic acid copy-number gain on chromosome 7 but not on chromosome 22. The tumor did not respond to chemotherapy or radiotherapy, and the patient survived for only 4 months after surgery. The present case of malignant RTs shows certain similarities with those of rhabdoid glioblastoma. Further accumulation and analysis of data, including data from genetic analyses, may lead to the identification of a new type of malignant RT.

1,7-Diethyl-4,10-diisopropyl-tetra-cene

The mol-ecule of the title compound, C(28)H(32), is located on a crystallographic inversion center. The ethyl groups are essentially coplanar with the tetra-cene ring, making a torsion angle of -0.4 (4)°. The isopropyl groups adopt an asymmetric conformation with their terminal methyl groups positioned on opposite sides of the tetra-cene plane [the Me-C-C-C torsion angles are -22.5 (4) and 100.9 (3)°]. In the crystal, the mol-ecules adopt an arrangement without significant π-π inter-actions along the stacking direction (y axis).

Dural cyst at the foramen magnum

A 69-year-old male presented with a rare dural cyst manifesting as numbness and pain in the limbs. Magnetic resonance imaging revealed a mass anterior to the medulla oblongata appearing as low intensity on T(1)-weighted and high intensity on T(2)-weighted imaging, with no enhancement. A cystic lesion ventral to the medulla oblongata was removed via the lateral suboccipital transcondylar approach. Histological examination showed the wall of the cyst consisted of fibrous connective tissue with a dense zone and a loose zone, similar to the structure found in the dura mater. The lesion was diagnosed as dural cyst. Dural cysts can be defined as cyst with the wall consisting of dura mater-like fibrous tissue, and attached to the dura mater. The origin of the present dural cyst was considered to be congenital.

Perimedullary arteriovenous fistula at the craniocervical junction - case report -

Perimedullary arteriovenous fistulas (AVFs) at the craniocervical junction are uncommon, and are often fed by the anterior spinal artery, with only a few cases fed by the intradural vertebral artery (VA). A 55-year-old man presented with a case of perimedullary AVF fed by the VA at the craniocervical junction manifesting as subarachnoid hemorrhage. Left vertebral angiography demonstrated an AVF supplied by branches from the VA. Three-dimensional computed tomography angiography (3D-CTA) revealed that the feeding arteries originated from the VA at the intradural position. Two feeding arteries were coagulated and dissected, followed by coagulation of a small feeder. The draining veins became discolored and shrank. 3D-CTA performed 2 months after the operation revealed disappearance of the AVF. Open surgery was successfully performed for the almost perimedullary AVF at the craniocervical junction, and is considered to be preferable for the treatment of this disease.

Intrasellar salivary gland-like pleomorphic adenoma: case report

BACKGROUND AND IMPORTANCE

We present a rare case of a patient with intrasellar salivary gland-like pleomorphic adenoma and review the 2 previously reported cases of the clinical entity to identify their common clinical features.

CLINICAL PRESENTATION

A 56-year-old Asian man visited our hospital with a chief complaint of visual disturbance caused by brain tumor that filled up the sella turcica with suprasellar extension. The patient underwent craniotomy via a left pterional approach, and the subdural, intracranial portion of the tumor was totally removed, with every artery and nerve preserved. Pathological diagnosis of the tumor was intrasellar salivary gland-like pleomorphic adenoma. Three years after the operation, the patient remains free from tumor recurrence.

CONCLUSION

Tumors in all 3 reported cases of intrasellar salivary gland-like pleomorphic adenoma, including the present case, showed suprasellar extension and compressed optic chiasm that resulted in visual disturbance of the patients. A calcified region inside the tumor on computed tomographic scanning was also a common finding. Differential diagnosis of intrasellar salivary gland-like pleomorphic adenomas should be considered in patients with calcified intrasellar tumors with suprasellar extension. The clinical entity seems to show good prognosis if surgically removed.

Assessment of cognitive function before and after surgery for posterior cranial fossa lesions using computerized and conventional tests

Cognitive function has not been well studied after neurosurgery for posterior fossa lesions despite its potential importance in determining surgical indications and approaches. The present study evaluated changes in cognitive functions after posterior fossa surgery to detect any differences between the middle cranial fossa and lateral suboccipital approaches in 50 patients with posterior fossa lesions such as tumors and vascular diseases. Twenty-five patients underwent surgery via the middle fossa and 25 via the lateral suboccipital approaches. Computerized test battery (CogState) and conventional neuropsychological tests (serial seven-word learning test and mini-mental state examination) were examined before, 1 month after, and 3 months after surgery. All scores of the neuropsychological tests remained within normal limits after surgery. However, the scores of one computerized test battery and serial seven-word learning tests decreased significantly 1 month after surgery and recovered within 3 months, indicating temporary deterioration of short-term memory in the middle fossa group. The computerized tests detected significantly larger numbers of patients with worsened results than the conventional tests. The middle fossa approach and operation time showed correlations with the postoperative neuropsychological declines. The computerized tests could be performed easily and were beneficial for detecting subtle changes of the cognitive function after surgery. Cognitive function, especially short-term memory, may decline temporarily with the middle fossa approach and long operation time.

Anterior transpetrosal approach to the prepontine epidermoids

We have operated on nine patients with a prepontine epidermoid extending to the bilateral cistern or the unilateral middle fossa using the anterior transpetrosal approach since 1986. The preoperative symptoms were unilateral trigeminal neuralgia, hearing disturbance, gait disturbance, double vision, facial hypesthesia, hemifacial spasm, and dysphagia. The most common neurological sign was unilateral trigeminal nerve disturbance. In two patients with useful hearing preoperatively lost, the labyrinth and mastoid air cells as well as the petrous apex were resected to extend the surgical field. Tumors were totally removed, except for capsules that were tightly adhered to the brain stem, cranial nerve, and vessels. The trigeminal neuralgia, hemifacial spasm, and dysphagia disappeared, but double vision improved only one out of three cases, and facial hypesthesia was unchanged in all cases. There were no postoperative deaths. New abducens palsy appeared in four cases and cerebrospinal fluid (CSF) leakage appeared in three cases postoperatively, but later these symptoms disappeared. In one case, postoperative chemical meningitis developed, and a ventricular shunt was required later to treat hydrocephalus. Postoperative follow-up, an average of 5,7 years, did not show any increases in any of the tumors. Based on our experience, we conclude that the anterior transpetrosal approach is more useful than the retromastoid suboccipital approach to resect the epidermoid located mainly in the prepontine cistern.

Dural and arachnoid membraneous protection of the abducens nerve at the petroclival region

The goal of this study was to determine the membranous protection of the abducens nerve in the petroclival region. The petroclival portion of the abducens nerve was studied in ten dissections from five cadaveric head specimens. One of the heads was used for histological sections. Four heads were injected with colored latex for microsurgical dissections. The histological sections were prepared from petroclival dura mater, embedded in paraffin blocks, stained, sectioned in the axial, coronal, and sagittal planes, and evaluated by light microscopy. The abducens nerve was covered by a dural sleeve and arachnoidal membrane during its course within the petroclival area. Following the petrous apex, the abducens nerve was fixed by a sympathetic plexus and connective tissue extensions to the lateral wall of the cavernous segment of the internal carotid artery and to the medial wall of Meckel's cave. Fibrous trabeculations inside the venous space were attached to the dural sleeve. The lateral clival artery accompanied the dural sleeve of the abducens nerve and supplied the petroclival dura mater. The arterioles accompanying the abducens nerve through the subarachnoid space supplied the nerve within the dural sleeve. The arachnoid membrane covered the abducens nerve within the dural sleeve to the petrous apex, and arachnoid granulations found on the dural sleeve protruded into the venous space. The extension of the arachnoid membrane to the petrous apex and the presence of arachnoid granulations on the dural sleeve suggest that the subarachnoid space continues in the dural sleeve.

Abnormal course of the oculomotor nerve on the clivus combined with a petroclival meningioma: case report

The course of the oculomotor nerve on the clivus was abnormal in a patient with petroclival meningioma. He complained of gait disturbance. A gadolinium-enhanced magnetic resonance image demonstrated a 4.4-cm enhancing mass in the petroclival region. The tumor was removed via an anterior transpetrosal-transtentorial approach. Normally, the oculomotor nerve originates from the brainstem and enters the oculomotor trigone. In this patient, the oculomotor nerve entered the dura mater at the upper clivus, behind the posterior clinoid process, and coursed parallel to the basilar artery. This entrance is lower than the normal entry point of the oculomotor nerve. The abnormal entrance of the oculomotor nerve may reflect an atypical developmental relationship among the cranial nerves, meninges, and bones during embryogenesis.

"Marking" the nitrogen atoms of phenyl-(2-pyridyl)-(3-pyridyl)-(4-pyridyl)-methane. Synthesis and absolute configuration of the corresponding tris(pyridine N-oxide)

To "mark" the nitrogen atoms in phenyl-(2-pyridyl)-(3-pyridyl)-(4-pyridyl)methane (1), we have synthesized the corresponding tris(pyridine N-oxide) 2 by oxidation of 1 with m-chloroperbenzoic acid. The nitrogen atoms of 2 are unequivocally determined by the X-ray crystal analysis of a single crystal of rac-2 whereas the nitrogen atoms cannot be assigned at all in the case of rac-1. N-Oxide 2 can be resolved by chiral high-performance liquid chromatography under similar conditions to those used for the resolution of 1. The calculated circular dichroism (CD) curve for (R)-2 on the basis of time-dependent density functional theory reproduces the experimental spectra very well to suggest that the second-eluted fraction ([CD(+)283]-2) is the R isomer, namely (R)-[CD(+)283]-2. The independent absolute configuration determinations for 1 and 2 are in keeping with the chemical correlation between the two compounds by oxidation of (R)-1 into (R)-2.

Functional analysis of HOXD9 in human gliomas and glioma cancer stem cells

Background

HOX genes encode a family of homeodomain-containing transcription factors involved in the determination of cell fate and identity during embryonic development. They also behave as oncogenes in some malignancies.

Results

In this study, we found high expression of the HOXD9 gene transcript in glioma cell lines and human glioma tissues by quantitative real-time PCR. Using immunohistochemistry, we observed HOXD9 protein expression in human brain tumor tissues, including astrocytomas and glioblastomas. To investigate the role of HOXD9 in gliomas, we silenced its expression in the glioma cell line U87 using HOXD9-specific siRNA, and observed decreased cell proliferation, cell cycle arrest, and induction of apoptosis. It was suggested that HOXD9 contributes to both cell proliferation and/or cell survival. The HOXD9 gene was highly expressed in a side population (SP) of SK-MG-1 cells that was previously identified as an enriched-cell fraction of glioma cancer stem-like cells. HOXD9 siRNA treatment of SK-MG-1 SP cells resulted in reduced cell proliferation. Finally, we cultured human glioma cancer stem cells (GCSCs) from patient specimens found with high expression of HOXD9 in GCSCs compared with normal astrocyte cells and neural stem/progenitor cells (NSPCs).

Conclusions

Our results suggest that HOXD9 may be a novel marker of GCSCs and cell proliferation and/or survival factor in gliomas and glioma cancer stem-like cells, and a potential therapeutic target.

Extraaxial neurocytoma in the skull base

Extraventricular neurocytoma is an uncommon neuronal tumor, located outside the cerebral ventricles, which shows histological features similar to those of central neurocytoma. Most extraventricular neurocytomas are situated in the intraaxial regions of the central nervous system. We report a rare case of an extraaxial neurocytoma in the sphenocavernous-petroclival region that was successfully treated by radiation therapy following partial removal and pathological evaluation of the tumor.

Single-copy gain of chromosome 1q is a negative prognostic marker in pediatric nonependymal, nonpilocytic gliomas

BACKGROUND

Reports of genetic analyses on pediatric gliomas are few, and those tumors have been far less characterized than adult gliomas.

OBJECTIVE

To characterize the genetic and biological features of pediatric gliomas.

METHODS

We investigated 23 pediatric nonependymal, nonpilocytic gliomas for chromosomal copy number aberrations (CNAs) by comparative genomic hybridization (CGH), mutations of isocitrate dehydrogenase (IDH) genes by direct sequencing, and proliferative activity and expression of O-methylguanine-DNA methyltransferase (MGMT) by immunohistochemistry.

RESULTS

The most frequent CNA was single-copy gain of chromosome 1q, with 10 of 20 successfully investigated tumors showing the abnormality (50%). Other CNAs detected by CGH included gain on 7q (+7q) in 6, +9q in 5, +17q in 5, and + 7p in 4 cases. Gain of entire chromosome 7 was rare (2 cases), and codeletion of 1p and 19q was not detected. Gain of 1q was significantly predictive for shorter progression-free survival (PFS) and overall survival (OS), and even more closely associated with poor clinical outcome than histological grade (P = .0009 for PFS, P = .003 for OS by 1q status; P = .004 for PFS, P = .035 for OS by high-grade vs low-grade). Gain of 1q was also significantly correlated with proliferative activity (P = .0002), and tumors with 1q gain showed a trend toward higher MGMT expression (P = .27). Mutation of IDH1 gene was detected in only 2 of 17 tumors successfully analyzed.

CONCLUSION

Single copy gain of 1q is associated with biological features of pediatric gliomas, and is a negative prognostic marker in patients with those tumors.