Ho-Shin Gwak

Silencing of MicroRNA-21 Confers Radio-Sensitivity through Inhibition of the PI3K/AKT Pathway and Enhancing Autophagy in Malignant Glioma Cell Lines

Radiation is a core part of therapy for malignant glioma and is often provided following debulking surgery. However, resistance to radiation occurs in most patients, and the underlying molecular mechanisms of radio-resistance are not fully understood. Here, we demonstrated that microRNA 21 (miR-21), a well-known onco-microRNA in malignant glioma, is one of the major players in radio-resistance. Radio-resistance in different malignant glioma cell lines measured by cytotoxic cell survival assay was closely associated with miR-21 expression level. Blocking miR-21 with anti-miR-21 resulted in radio-sensitization of U373 and U87 cells, whereas overexpression of miR-21 lead to a decrease in radio-sensitivity of LN18 and LN428 cells. Anti-miR-21 sustained γ-H2AX DNA foci formation, which is an indicator of double-strand DNA damage, up to 24 hours and suppressed phospho-Akt (ser473) expression after exposure to γ-irradiation. In a cell cycle analysis, a significant increase in the G2/M phase transition by anti-miR-21 was observed at 48 hours after irradiation. Interestingly, our results showed that anti-miR-21 increased factors associated with autophagosome formation and autophagy activity, which was measured by acid vesicular organelles, LC3 protein expression, and the percentage of GFP-LC3 positive cells. Furthermore, augmented autophagy by anti-miR-21 resulted in an increase in the apoptotic population after irradiation. Our results show that miR-21 is a pivotal molecule for circumventing radiation-induced cell death in malignant glioma cells through the regulation of autophagy and provide a novel phenomenon for the acquisition of radio-resistance.

Meningioma manifesting intracerebral haemorrhage: a possible mechanism of haemorrhage.

Summary¶ We present a possible mechanism of intracerebral peritumoural haemorrhage in meningioma based on the clinical data of three of our cases. A meningioma manifesting intracerebral haemorrhage is uncommon and some sporadic case reports have been presented, but without any proven mechanisms. We are presenting three cases of convexity meningioma manifesting spontaneous intracerebral haemorrhage with apoplectiform onset. All three patients had no evidence of bleeding tendency or other predisposing factors for haemorrhage. Preoperative radiological studies showed a solid mass attached to the dura with intracerebral peritumoural haematoma. Total removal of the tumour and haematoma could be achieved in every case. Histological investigation revealed extensive tumour infarction in two cases and fibrosis related to pre-existing ischaemia in the other case. The diagnoses were atypical meningioma in two cases and transitional type in one case. We suggest that extensive tumour infarction might be a cause of spontaneous intracerebral peritumoural haemorrhage in our series of patients.

Gamma knife radiosurgery for brain metastases: prognostic factors for survival and local control

The purpose of this paper was to note a potential source of error in magnetic resonance (MR) imaging. Magnetic resonance images were acquired for stereotactic planning for GKS of a vestibular schwannoma in a female patient. The images were acquired using three-dimensional sequence, which has been shown to produce minimal distortion effects. The images were transferred to the planning workstation, but the coronal images were rejected. By examination of the raw data and reconstruction of sagittal images through the localizer side plate, it was clearly seen that the image of the square localizer system was grossly distorted. The patient was returned to the MR imager for further studies and a metal clasp on her brassiere was identified as the cause of the distortion.A-60-year-old man with medically intractable left-sided maxillary division trigeminal neuralgia had severe cardiac disease, was dependent on an internal defibrillator and could not undergo magnetic resonance imaging. The patient was successfully treated using computerized tomography (CT) cisternography and gamma knife radiosurgery. The patient was pain free 2 months after GKS. Contrast cisternography with CT scanning is an excellent alternative imaging modality for the treatment of patients with intractable trigeminal neuralgia who are unable to undergo MR imaging.The authors describe acute deterioration in facial and acoustic neuropathies following radiosurgery for acoustic neuromas. In May 1995, a 26-year-old man, who had no evidence of neurofibromatosis Type 2, was treated with gamma knife radiosurgery (GKS; maximum dose 20 Gy and margin dose 14 Gy) for a right-sided intracanalicular acoustic tumor. Two days after the treatment, he developed headache, vomiting, right-sided facial weakness, tinnitus, and right hearing loss. There was a deterioration of facial nerve function and hearing function from pretreatment values. The facial function worsened from House-Brackmann Grade 1 to 3. Hearing deteriorated from Grade 1 to 5. Magnetic resonance (MR) images, obtained at the same time revealed an obvious decrease in contrast enhancement of the tumor without any change in tumor size or peritumoral edema. Facial nerve function improved gradually and increased to House-Brackmann Grade 2 by 8 months post-GKS. The tumor has been unchanged in size for 5 years, and facial nerve function has also been maintained at Grade 2 with unchanged deafness. This is the first detailed report of immediate facial neuropathy after GKS for acoustic neuroma and MR imaging revealing early possibly toxic changes. Potential explanations for this phenomenon are presented.In clinical follow-up studies after radiosurgery, imaging modalities such as computerized tomography (CT) and magnetic resonance (MR) imaging are used. Accurate determination of the residual lesion volume is necessary for realistic assessment of the effects of treatment. Usually, the diameters rather than the volume of the lesion are measured. To determine the lesion volume without using stereotactically defined images, the software program VOLUMESERIES has been developed. VOLUMESERIES is a personal computer-based image analysis tool. Acquired DICOM CT scans and MR image series can be visualized. The region of interest is contoured with the help of the mouse, and then the system calculates the volume of the contoured region and the total volume is given in cubic centimeters. The defined volume is also displayed in reconstructed sagittal and coronal slices. In addition, distance measurements can be performed to measure tumor extent. The accuracy of VOLUMESERIES was checked against stereotactically defined images in the Leksell GammaPlan treatment planning program. A discrepancy in target volumes of approximately 8% was observed between the two methods. This discrepancy is of lesser interest because the method is used to determine the course of the target volume over time, rather than the absolute volume. Moreover, it could be shown that the method was more sensitive than the tumor diameter measurements currently in use. VOLUMESERIES appears to be a valuable tool for assessing residual lesion volume on follow-up images after gamma knife radiosurgery while avoiding the need for stereotactic definition.This study was conducted to evaluate the geometric distortion of angiographic images created from a commonly used digital x-ray imaging system and the performance of a commercially available distortion-correction computer program. A 12 x 12 x 12-cm wood phantom was constructed. Lead shots, 2 mm in diameter, were attached to the surfaces of the phantom. The phantom was then placed inside the angiographic localizer. Cut films (frontal and lateral analog films) of the phantom were obtained. The films were analyzed using GammaPlan target series 4.12. The same procedure was repeated with a digital x-ray imaging system equipped with a computer program to correct the geometric distortion. The distortion of the two sets of digital images was evaluated using the coordinates of the lead shots from the cut films as references. The coordinates of all lead shots obtained from digital images and corrected by the computer program coincided within 0.5 mm of those obtained from cut films. The average difference is 0.28 mm with a standard deviation of 0.01 mm. On the other hand, the coordinates obtained from digital images with and without correction can differ by as much as 3.4 mm. The average difference is 1.53 mm, with a standard deviation of 0.67 mm. The investigated computer program can reduce the geometric distortion of digital images from a commonly used x-ray imaging system to less than 0.5 mm. Therefore, they are suitable for the localization of arteriovenous malformations and other vascular targets in gamma knife radiosurgery.

Sulindac and its metabolites inhibit invasion of glioblastoma cells via down‐regulation of Akt/PKB and MMP‐2

Non‐steroidal anti‐inflammatory drug (NSAID), sulindac has chemopreventive and anti‐tumorigenic properties, however, the molecular mechanism of this inhibitory action has not been clearly defined. The Akt/protein kinase B, serine/threonine kinase is well known as an important mediator of many cell survival signaling pathways. In the present study, we demonstrate that down‐regulation of Akt is a major effect of anti‐invasiveness property of sulindac and its metabolites in glioblastoma cells. Myristoylated Akt (MyrAkt) transfected U87MG glioblastoma cells showed increase invasiveness, whereas DN‐Akt transfected cells showed decrease invasiveness indicating that Akt potently promoted glioblastoma cell invasion. MMP‐2 promoter and enzyme activity were up‐regulated in Akt kinase activity dependent manner. Sulindac and its metabolites down‐regulated Akt phosphorylation, inhibited MMP‐2 production, and significantly inhibited invasiveness of human glioblastoma cells. In addition, sulindac and LY294002, a selective inhibitor of phosphoinositide 3‐kinase (PI3K), synergistically inhibited the invasion of glioblastoma cells. Furthermore, only celecoxib showed Akt phosphorylation reduction and an anti‐invasivness in glioblastoma cells, whereas aspirin, ketoprofen, ketorolac, and naproxen did not. In conclusion, our results provide evidence that down‐regulation of Akt pathway and MMP‐2 may be one of the mechanisms by which sulindac and its metabolites inhibit glioblastoma cell invasion.

Arsenic trioxide sensitizes CD95/Fas‐induced apoptosis through ROS‐mediated upregulation of CD95/Fas by NF‐κB activation

CD95/Fas is a cell surface protein that belongs to the tumor necrosis factor receptor family. Signals through CD95/Fas are able to induce apoptosis in sensitive cells. Therefore, modalities to regulate the CD95/Fas expression level in tumor cells are called for. In the present study, we show that sublethal doses of arsenic trioxide (As2O3) sensitized CD95/Fas‐induced apoptosis in human cervical cancer cells, and the sensitizing effects resulted from As2O3‐mediated increase in the expression of the CD95/Fas. N‐acetyl‐L‐cysteine, a specific scavenger of reactive oxygen species, abrogated As2O3‐induced upregulation of CD95/Fas and enhancement of CD95/Fas‐mediated apoptosis. Furthermore, inhibition of NF‐κB by transient transfection of IκBα supersuppressor blocked the increase of CD95/Fas expression following As2O3 treatment. Antisense oligonucleotide of CD95/Fas and ZB4, an antibody that blocks the binding of CD95/Fas ligand to CD95/Fas, reduced the amount of As2O3‐sensitized CD95/Fas‐induced apoptosis, demonstrating the specificity of CD95/Fas‐binding ligands in the As2O3‐sensitized CD95/Fas‐induced apoptosis. These findings demonstrate that sensitization of human cervical cancer cells to CD95/Fas‐mediated apoptosis by As2O3 can be partly due to induction of ROS and subsequent upregulation of CD95/Fas gene expression by NF‐κB activation.

Analysis of treatment outcomes of intraventricular chemotherapy in 105 patients for leptomeningeal carcinomatosis from non-small-cell lung cancer.

Introduction: Reports on the treatment result of leptomeningeal carcinomatosis (LMC) from a single primary cancer are rare and mixed treatment modalities make it even more difficult to interpret the results properly. Here, we report clinical outcomes of an intraventricular chemotherapy for LMC from non–small-cell lung cancer. Methods: Medical records of 105 patients were retrieved and retrospectively analyzed to find the prognostic factors of patients’ survival and symptom responses, including intracranial pressure (ICP) control. Results: There were 44 men and 61 women, with a median age of 56 years (range, 31–75 years). Patients received a median five rounds of intraventricular chemotherapy (range, 1–49 rounds). The most common presenting symptom was headache (77%) with nausea or vomiting, which showed the highest response rate of 42%. Altered mentality (36%), cranial neuropathy (15%), and cauda equina symptoms (12%) revealed 10% or less of symptom response. Only eight patients (7.6%) showed negative conversion of cerebrospinal fluid cytology. Median overall survival was 3.0 months (range, 0.5–21.5 months). Age (≥60 years), poor Karnofsky performance score (< 70), and uncontrolled ICP were found to be unfavorable prognostic factors for patient survival. A greater amount of intraventricular chemotherapy, which was evaluated as time-dependent covariate, and concurrent systemic chemotherapy significantly improved overall survival in the multivariable analysis. Conclusion: Intraventricular chemotherapy for patients with LMC from non–small-cell lung cancer could palliate associated symptoms and prolong patients’ survival. Careful selection of patients for intraventricular chemotherapy is recommended with aggressive ICP control and concurrent systemic chemotherapy.

Diarsenic and tetraarsenic oxide inhibit cell cycle progression and bFGF- and VEGF-induced proliferation of human endothelial cells.

Arsenic trioxide (As2O3, diarsenic oxide) has recently been reported to induce apoptosis and inhibit the proliferation of various human cancer cells derived from solid tumors as well as hematopoietic malignancies. In this study, the in vitro effects of As2O3 and tetraasrsenic oxide (As4O6) on cell cycle regulation and basic fibroblast growth factor (bFGF)‐ or vascular endothelial growth factor (VEGF)‐stimulated cell proliferation of human umbilical vein endothelial cells (HUVEC) were investigated. Significant dose‐dependent inhibition of cell proliferation was observed when HUVEC were treated with either arsenical compound for 48 h, and flow cytometric analysis revealed that these two arsenical compounds induced cell cycle arrest at the G1 and G2/M phases—the increases in cell population at the G1 and G2/M phase were dominantly observed in As2O3‐ and As4O6‐treated cells, respectively. In both arsenical compounds‐treated cells, the protein levels of cyclin A and CDC25C were significantly reduced in a dose‐dependent manner, concomitant to the reduced activities of CDK2‐ and CDC2‐associated kinase. In G1‐synchronized HUVEC, the arsenical compounds prevented the cell cycle progression from G1 to S phase, which was stimulated by bFGF or VEGF, through the inhibition of growth factor‐dependent signaling. These results suggest that arsenical compounds inhibit the proliferation of HUVEC via G1 and G2/M phase arrest of the cell cycle. In addition, these inhibitory effects on bFGF‐ or VEGF‐stimulated cell proliferation suggest antiangiogenic potential of these arsenical compounds.

ACNU–cisplatin Continuous Infusion Chemotherapy as Salvage Therapy for Recurrent Glioblastomas: Phase II Study

SummaryPurpose: To evaluate the activity and the toxicity of ACNU (1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-cholroethyl)-3-nitrosourea hydrochloride) administered with cisplatin by intravenous infusion for 72 h in select patients with recurrent glioblastoma.Patients and methods: From April 1996 to 2002, 37 patients with histologically proven glioblastoma, who showed recurrence on image study after operation and radiation, met the eligibility criteria of our cohort. The mean time to recurrence was 9.7±7.0 (1–26 months). Treatment response was evaluated every 6 weeks using magnetic resonance imaging (MRI). Complete blood counts were collected every week to monitor and treat possible bone marrow suppression from the treatment. Survival rates were analyzed using the Kaplan–Meier and log rank test.Results: Post-chemotherapy MRI was available in 36 of 37 patients. Response to treatment was observed in 19 patients (53%) including two cases of complete remission. Six patients (17%) showed progression (PD) and 11 patients (31%) had stable disease (SD). Two or more cycles of chemotherapy was the only factor that predicted response to treatment. The overall median survival for all patients was 17.0±5.5 months. Age (< 40 years) and time to recurrence (≥1 year) were the clinical factors that predicted improved overall survival. Survival gain after chemotherapy was 9 months. Patients who responded and those with SD after treatment (11 months) had a longer median survival compared to PD (5 months) (P=0.01). Myelosuppression was severe (grade III/IV leukopenia in 15 patients (40%) and grade III/IV thrombocytopenia in 19 patients (52%)) but most recovered more than WHO grade II at the end of the chemotherapy cycles. There was only one fatality due to sepsis from pneumonia during the initial leukopenic state.Conclusion: ACNU and cisplatin chemotherapy can be an effective salvage therapy for recurrent glioblastoma patients. Myelosuppression from the chemotherapy regimen was the greatest side-effect but was manageable.

Long-term outcome of trigeminal neurinomas with modified classification focusing on petrous erosion

BACKGROUND The authors present a retrospective analysis of 29 consecutive patients with trigeminal neurinomas. Modified classification based on the tumor distribution over petrous ridge is suggested to select the optimal surgical approach and to predict the outcome. METHODS Preoperative computed tomography (CT) or magnetic resonance (MR) images were analyzed to measure a long diameter of tumor axis (LD), which divided into middle and posterior fossa and a width of the petrous erosion (PW) by the tumor on axial image. The tumors were classified into four groups (M, tumor confined to middle fossa; Mp, tumor mainly in middle fossa; M = P, tumor equally distributed into both middle and posterior fossa; Pm, tumor mainly in cisternal space of posterior fossa with slender, rarely round extension into Meckels cave), and extent of removal was compared between the groups. Long-term outcomes were based on recurrence-free survival. RESULTS Total removal was achieved in 16 patients including stage operation (55%). Excluding three tumors, which underwent gamma knife for residual tumor, 8 of 10 subtotally removed tumors recurred at 50 months on average. The LD and PW are significantly different among the tumor types. The M = P type is the largest in both parameter, while the M type is the smallest in LD; Pm type is the smallest in PW, respectively. The tumors with equal or lager posterior fossa component (M = P and Pm type) were more difficult to remove totally by single attempt than those with smaller or nil posterior fossa mass (Mp and M type). Also, the corrected PW (PW over the tumor diameter of minor portion) shows a tendency to influence the extent of removal as the relatively narrow PW hindered the total removal. CONCLUSIONS Aggressive attempt for total removal using skull base approach is recommended, especially for those having dominant posterior fossa component and for those having relatively narrow PW.

Incidence and risk factors for leptomeningeal carcinomatosis in breast cancer patients with parenchymal brain metastases.

Objective The objective of study is to evaluate the incidence of leptomeningeal carcinomatosis (LMC) in breast cancer patients with parenchymal brain metastases (PBM) and clinical risk factors for the development of LMC. Methods We retrospectively analyzed 27 patients who had undergone surgical resection (SR) and 156 patients with whole brain radiation therapy (WBRT) as an initial treatment for their PBM from breast cancer in our institution and compared the difference of incidence of LMC according to clinical factors. The diagnosis of LMC was made by cerebrospinal fluid cytology and/or magnetic resonance imaging. Results A total of 27 patients (14%) in the study population developed LMC at a median of 6.0 months (range, 1.0-50). Ten of 27 patients (37%) developed LMC after SR, whereas 17 of 156 (11%) patients who received WBRT were diagnosed with LMC after the index procedure. The incidence of LMC was significantly higher in the SR group compared with the WBRT group and the hazard ratio was 2.95 (95% confidence interval; 1.33-6.54, p<0.01). Three additional factors were identified in the multivariable analysis : the younger age group (<40 years old), the progressing systemic disease showed significantly increased incidence of LMC, whereas the adjuvant chemotherapy reduce the incidence. Conclusion There is an increased risk of LMC after SR for PBM from breast cancer compared with WBRT. The young age (<40) and systemic burden of cancer in terms of progressing systemic disease without adjuvant chemotherapy could be additional risk factors for the development of LMC.