MiR-181b sensitizes glioma cells to teniposide by targeting MDM2.

BACKGROUND: Although the incidence of glioma is relatively low, it is the most malignant tumor of the central nervous system. The prognosis of high-grade glioma patient is very poor due to the difficulties in complete resection and resistance to radio-/chemotherapy. Therefore, it is worth investigating the molecular mechanisms involved in glioma drug resistance. MicroRNAs have been found to play important roles in tumor progression and drug resistance. Our previous work showed that miR-181b is involved in the regulation of temozolomide resistance. In the current study, we investigated whether miR-181b also plays a role in antagonizing the effect of teniposide. METHODS: MiR-181b expression was measured in 90 glioma patient tissues and its relationship to prognosis of these patients was analyzed. Cell sensitivity to teniposide was tested in 48 primary cultured glioma samples. Then miR-181b stably overexpressed U87 cells were generated. The candidate genes of miR-181b from our previous study were reanalyzed, and the interaction between miR-181b and target gene MDM2 was confirmed by dual luciferase assay. Cell sensitivity to teniposide was detected on miR-181b over expressed and MDM2 down regulated cells. RESULTS: Our data confirmed the low expression levels of miR-181b in high-grade glioma tissues, which is related to teniposide resistance in primary cultured glioma cells. Overexpression of miR-181b increased glioma cell sensitivity to teniposide. Through target gene prediction, we found that MDM2 is a candidate target of miR-181b. MDM2 knockdown mimicked the sensitization effect of miR-181b. Further study revealed that miR-181b binds to the 3'-UTR region of MDM2 leading to the decrease in MDM2 levels and subsequent increase in teniposide sensitivity. Partial restoration of MDM2 attenuated the sensitivity enhancement by miR-181b. CONCLUSIONS: MiR-181b is an important positive regulator on glioma cell sensitivity to teniposide. It confers glioma cell sensitivity to teniposide through binding to the 3'-UTR region of MDM2 leading to its reduced expression. Our findings not only reveal the novel mechanism involved in teniposide resistance, but also shed light on the optimization of glioma treatment in the future.

Clinical significance of vasculogenic mimicry in human gliomas.

Vasculogenic mimicry (VM) is known as non-endothelial tumor cell-lined microvascular channels in aggressive tumors. We have previously found the presence of VM in high-grade gliomas. In this study, we aimed to identify VM patterns in gliomas and to explore their clinical significance. Tumor samples as well as their detailed clinical/prognostic data were collected from 101 patients. Vasculogenic mimicry in the glioma samples was determined by dual staining for endothelial marker CD34 and periodic acid-Schiff (PAS). Tumor samples were also immunohistochemically stained for Ki-67, VEGF, COX-2 and MMP-9. The association between VM and the clinical characteristics of the patients were analyzed. A Kaplan-Meier survival analysis and log-rank tests were performed to compare survival times of the patients. Vasculogenic mimicry was present in 13 out of 101 samples. The higher grade gliomas had a higher incidence of VM than that of lower grade gliomas (P = 0.006). Vasculogenic mimicry channels were associated with the expression of COX-2 and MMP-9 (P < 0.05). While there was no association between the existence of VM and the sex, age and preoperative epilepsy of the patients, or expression of Ki-67 and VEGF. However, patients with VM-positive gliomas survived a shorter period of time than those with VM negative gliomas (P = 0.027). Interestingly, in high-grade gliomas, the level of microvascular density was lower in VM positive tumors than those VM negative tumors (P = 0.039). Our results suggest that VM channels in gliomas correlate with increasing malignancy and higher aggressiveness, and may provide a complementation to the tumor's blood supply, especially in less vascularized regions, which may aid in the identification of glioma patients with a poorer prognosis.

[Nimotuzumab in combination with chemotherapy for patients with malignant gliomas].

OBJECTIVE: Nimotuzumab is a humanized monoclonal antibody targeted against epidermal growth factor receptor (EGFR). Recent clinical studies show that patients with malignant gliomas could benefit from nimotuzumab treatment. The aim of the present study was to evaluate the efficacy and side effects of nimotuzumab in combination with chemotherapy for patients with malignant gliomas. METHODS: The patients received 200 mg of nimotuzumab infusion intravenously over 60 minutes once weekly for the first eight weeks and then once every two weeks until unacceptable toxicity or tumor progression occurred. Individualized chemotherapy was administered based on O(6)-methylguanine-DNA methyltransferase (MGMT) expression and previous chemotherapy responses in combined with nimotuzumab. RESULTS: Fourteen patients received a total of 122 times of nimotuzumab ranging from 2 to 20 (median 7.5 times). Combined chemotherapy regimens included: continuous 21-day temozolomide (10 cases), standard 5-day temozolomide (2 cases), teniposide plus cisplatin (1 case), and teniposide plus nimustine (1 case). Partial response (PR) and stable disease (SD) were found in 3 patients (21.4%)and 6 patients (42.9%), respectively. Disease control rate (PR + SD) was 64.3%. The median progression-free survival (PFS) was 4 months (95%CI: 0.7 - 7.3) and PFS at 6 months was 30.6%. The most common toxicities include grade I-II neutropenia (2 cases), thrombocytopenia (2 cases), lymphopenia (1 case), nausea and vomitting (3 case) and asymptomatic transaminase increase (1 case). One patient developed grade IV neutropenia and thrombocytopenia. One patient developed nimotuzumab-related acneiform rash. CONCLUSIONS: Nimotuzumab in combination with chemotherapy has moderate activity in patients with malignant gliomas and the toxicities are well tolerable, therefore, worth further investigation.

Working memory and the identification of facial expression in patients with left frontal glioma.

Patients with brain tumors may have cognitive dysfunctions including memory deterioration, such as working memory, that affect quality of life. This study was to explore the presence of defects in working memory and the identification of facial expressions in patients with left frontal glioma. This case-control study recruited 11 matched pairs of patients and healthy control subjects (mean age ± standard deviation, 37.00 ± 10.96 years vs 36.73 ± 11.20 years; 7 male and 4 female) from March through December 2011. The psychological tests contained tests that estimate verbal/visual-spatial working memory, executive function, and the identification of facial expressions. According to the paired samples analysis, there were no differences in the anxiety and depression scores or in the intelligence quotients between the 2 groups (P > .05). All indices of the Digit Span Test were significantly worse in patients than in control subjects (P < .05), but the Tapping Test scores did not differ between patient and control groups. Of all 7 Wisconsin Card Sorting Test (WCST) indexes, only the Preservative Response was significantly different between patients and control subjects (P < .05). Patients were significantly less accurate in detecting angry facial expressions than were control subjects (30.3% vs 57.6%; P < .05) but showed no deficits in the identification of other expressions. The backward indexes of the Digit Span Test were associated with emotion scores and tumor size and grade (P < .05). Patients with left frontal glioma had deficits in verbal working memory and the ability to identify anger. These may have resulted from damage to functional frontal cortex regions, in which roles in these 2 capabilities have not been confirmed. However, verbal working memory performance might be affected by emotional and tumor-related factors.

Serum CCL2 and serum TNF-α--two new biomarkers predict bone invasion, post-treatment distant metastasis and poor overall survival in nasopharyngeal carcinoma.

PURPOSE: To evaluate the prognostic potential of serum CCL2 (sCCL2) and serum TNF-α (sTNF-α) in nasopharyngeal carcinoma (NPC) before treatment by analysing the expression of these two markers. EXPERIMENTAL DESIGN: Both sCCL2 and sTNF-α were prospectively detected in 297 NPC patients with enzyme-linked immunosorbent assay (ELISA) before treatment. The correlations between sCCL2 level or sTNF-α level and patient's survival were evaluated. RESULTS: For sCCL2, the 5-year overall survival (OS) and 5-year distant metastasis-free survival (DMFS) of high expression group and low expression group were 64% versus 81% and 67% versus 84% (P < 0.05), respectively. For sTNF-α, the 5-year OS and 5-year DMFS of high expression group and low expression group were 62% versus 79% and 66% versus 82% (P < 0.05), respectively. The 5-year OS and 5-year DMFS for both positive patients, one marker positive patient and both negative patients were 53% versus 77% versus 85% and 58% versus 80% versus 86% (P < 0.05), respectively. Concentrations of sCCL2 and sTNF-α in patients with large skull base invasion were higher than those without or with small skull invasion (P < 0.05). Patients who developed bone metastasis alone after radical treatment had higher pre-treatment concentrations of sCCL2 and sTNF-α than those without metastasis (P < 0.001). Multifactorial Cox regression analyses demonstrated that T/N/M classification, chemotherapy, sCCL2 level and sTNF-α level were independent predictors of OS and DMFS of NPC patients. CONCLUSION: High expression levels of sCCL2 and sTNF-α predict bone invasion, post-treatment distant metastasis and poor overall survival in NPC patients.

Sensitization of glioma cells to tamoxifen-induced apoptosis by Pl3-kinase inhibitor through the GSK-3ß/ß-catenin signaling pathway.

Malignant gliomas represent one of the most aggressive types of cancers and their recurrence is closely linked to acquired therapeutic resistance. A combination of chemotherapy is considered a promising therapeutic model in overcoming therapeutic resistance and enhancing treatment efficacy. Herein, we show by colony formation, Hochest 33342 and TUNEL staining, as well as by flow cytometric analysis, that LY294002, a specific phosphatidylinositide-3-kinase (PI3K) inhibitor, enhanced significantly the sensitization of a traditional cytotoxic chemotherapeutic agent, tamoxifen-induced apoptosis in C6 glioma cells. Activation of PI3K signaling pathway by IGF-1 protected U251 cells from apoptosis induced by combination treatment of LY294002 and tamoxifen. Interference of PI3K signaling pathway by PI3K subunit P85 siRNA enhanced the sensitization of U251 glioma cells to tamoxifen -induced apoptosis. By Western blotting, we found that combination treatment showed lower levels of phosphorylated Akt(Ser473) and GSK-3ß(Ser9) than a single treatment of LY294002. Further, we showed a significant decrease of nuclear ß-catenin by combination treatment. In response to the inhibition of ß-catenin signaling, mRNA and protein levels of Survivin and the other three antiapoptotic genes Bcl-2, Bcl-xL, and Mcl-1 were significantly decreased by combination treatment. Our results indicated that the synergistic cytotoxic effect of LY294002 and tamoxifen is achieved by the inhibition of GSK-3ß/ß-catenin signaling pathway.

Activities of DNA-PK and Ku86, but not Ku70, may predict sensitivity to cisplatin in human gliomas.

OBJECTIVE: This study was designed to investigate the relationship between activities of DNA-dependent protein kinase (DNA-PK), its subunits Ku86/Ku70, and sensitivities to cisplatin in human glioma samples. METHODS: Thirty-six glioma samples from patients without prior treatment before neurosurgery were included in this study. The sensitivities to cisplatin as indicated by IC(50) (the inhibitory concentration leading to 50% cell death) were assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenytetrazolium (MTT) assay; activities of DNA-PK and Ku70/Ku86 were analyzed by SigmaTECT DNA-Dependent Protein Kinase Assay System and Ku70/Ku86 DNA Repair Kit, respectively. RESULTS: Sensitivities to cisplatin correlated with the activities of DNA-PK/Ku86, but not with the Ku70 or other clinical parameters such as age, sex of the patients, pathological gradings of the tumors, or tumor size. The levels of DNA-PK activities also associated with pathological grading and Ku86, but not with other clinical parameters. The tumors of the patients who failed to respond to cisplatin-based chemotherapy tended to display higher activity levels of DNA-PK and Ku86. Furthermore, platinum-based chemotherapy did not result in significant changes of DNA-PK/Ku activities in four matched samples before and after chemotherapy. CONCLUSION: Pretreatment determination of DNA-PK/Ku86 activities might be helpful in identifying patients who will actually benefit from platinum-based treatment.

[Postoperative diabetes insipidus after transsphenoidal resection of pituitary tumor].

OBJECTIVE: To study the prevention and treatment of postoperative diabetes insipidus after removal of pituitary tumor through transsphenoidal operation, to decrease the incidence of postoperative complications and improve the treatment of pituitary tumor. METHODS: The clinical data of 86 cases of transsphenoidal resection of pituitary tumor in recent 8 years were retrospectively reviewed, including 35 endoscopic operation and 51 microscopic operation. The incidence, prevention and treatment of diabetes insipidus were statistically analysed. RESULTS: There were 18 cases of postoperative diabetes insipidus in total of 86 operations, including 15 acute cases, 3 delayed cases. Twelve were temporary , which recovered within 1 week. After prompt treatment, 14 recovered within 1 week, 4 recovered within 2 weeks. No persistent diabetes insipidus was found. CONCLUSIONS: The key points to prevent postoperative diabetes insipidus lay in the improvement of operative skills, careful protection during operation and avoidance of unnecessary injury. In case of diabetes insipidus occurred, rational use of antidiuretics and correction of electrolyte balance were effective in the treatment of postoperative diabetes insipidus.

[Individualized chemotherapy based on drug sensitivity and resistance assay and MGMT protein expression for patients with malignant glioma--analysis of 42 cases].

BACKGROUND & OBJECTIVE: Malignant glioma cells are resistant to most chemotherapeutic agents. Nitrosourea and temozolomide (TMZ) are main agents for treating malignant glioma. Resistance of malignant glioma to these agents is frequently associated with high levels of DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT). This study was to evaluate the efficacy of individualized chemotherapy, according to chemotherapy sensitivity and resistance assays (CSRAs) and MGMT expression pattern, on malignant glioma, and observe the adverse events. METHODS: The pathologically confirmed malignant glioma patients, treated by operation at Cancer Center of Sun Yat-sen University from Dec. 2001 to Feb. 2006, were enrolled. The fresh tumor tissues obtained during operation were immediately sent for CSRAs using MTT assay. The expression of MGMT protein was detected by immunohistochemistry. After radiotherapy,the patients received chemotherapy according to the results of CSRAs and MGMT expression. The patients were evaluated for response to chemotherapy according to WHO criteria, and for toxicity according to National Cancer Institute (NCI) criteria. RESULTS: Forty-two patients were evaluated for response to chemotherapy. Seven patients received 2 chemotherapy regimens consecutively, therefore, overall 49 cases were evaluable. Of the 49 cases, 6 (12%) achieved complete remission (CR), 10 (20%) achieved partial remission (PR), 20 (41%) had stable disease (SD), and 13 (27%) had progressive disease (PD). The objective response rate (CR and PR) was 33%, and the disease control rate (CR, PR, and SD) was 73%. Hematologic toxicities were the main adverse events observed in this study, included grade IV anemia (1%), grade III-IV leukopenia (28%), and grade III-IV thrombocytopenia (8%). Non-hematologic toxicities mainly included nausea/vomit, fatigue, and alopecia. CONCLUSION: Individualized chemotherapy based on in vitro CSRAs and MGMT expression for patients with malignant glioma could improve overall response rate.

[Expression of costimulator 4-1BBL and B7-1 on glioma cell lines].

BACKGROUND & OBJECTIVE: Costimulatory molecules 4-1BBL and B7-1 have been proposed to be therapeutic targets to improve and sustain antitumor immune response. This study was to investigate the expression of 4-1BBL and B7-1 on several glioma cell lines. METHODS: The expression of 4-1BBL and B7-1 on glioma cell lines T98G, MGR2, MGR1, SF767, SKMG1, SKMG4, and UW28 was detected by flow cytometry. The cytotoxic effects of vincristine (VCR) on the glioma cell lines were assessed with MTT assay. The correlation of 4-1BBL expression to drug resistance was analyzed. RESULTS: The 7 glioma cell lines showed various levels of 4-1BBL expression, but none expressed B7-1. The positive rate of 4-1BBL was above 30% in T98G and MGR1 cells which were resistant to VCR; while it was below 10% in MGR2, SF767, SKMG1, SKMG4, and UW28 cells which were sensitive to VCR. CONCLUSIONS: All of the detected cell lines express 4-1BBL, but none expresses B7-1. The glioma cells with high 4-1BBL expression are resistant to VCR.

[Microneurosurgical treatment for gliomas located in lateral fissure area].

BACKGROUND & OBJECTIVE: It has been generally recognized that extensive resection for gliomas is directly associated with better prognosis of the patients. However, some tumors in functional area are not easy to be radically resected and neurological deficiency could be resulted by surgery. This study was designed to investigate whether gliomas located in lateral fissure area could be radically resected without neurological deficiency. METHODS: There were 22 gliomas located in lateral fissure area underwent microsurgical resection. The main branches of middle cerebral artery were preserved and the patients, if any neurological disfunction occurrence, were treated accordingly. RESULTS: All 22 gliomas were totally or subtotally resected using microneurosurgical technique. In 7 cases the reserved functional vessels which pass through tumor mass, look like "bridge" after tumor resection. Six patients resulted in motor disfunction following surgery, in which 5 cases were recovered and KPS reached 70 after 6 months. CONCLUSION: Gliomas located in lateral fissure area could be radically resected under microscope resulting no neurological deficiency, if any, will recover.

[Microsurgical technique of brain glioma---a report of 183 cases].

BACKGROUND & OBJECTIVE: Prognosis of glioma is still poor, its main treatment is surgery. The extent of tumor resection relates with prognosis. This study was to evaluate the extent of resection, post-operative Karnofsky performance scale (KPS), and survival rate of the glioma patients received microsurgery. METHODS: Records of 183 glioma patients received microneurosurgery were retrospectively analyzed, the extent of resection, post-operative KPS, and survival rate of patients were evaluated. Different microsurgical techniques were applied according to the location of gliomas. En bloc resection was performed for gliomas in non-functional areas by dissecting the tumors along edema area with high-power bipolar electrocoagulation. The tumors in functional areas were separated along cortex sulcus, the central part of tumor was removed firstly, and residual part was resected with low-power electrocoagulation. Gliomas close to important vessels were sucked, and electrocoagulation seldom performed. RESULTS: Among 183 cases of glioma, 85 in non-functional area, 47 in functional area, and 51 close to important vessels. Total and sub-total resection was performed in 163 patients (89.1%). The average post-operative KPS was 74. The KPS was decreased in 23 patients, increased in 44 patients, and stable in 116 patients. Patients were followed up for 12-216 months with an average of 47.8 months. The follow-up rate was 100%. Among 113 patients with long-term follow-up (>/=5 years), 5-year survival rates of low-grade, and high-grade astrocytoma patients were 75.4% (52/69), and 18.2% (8/44). CONCLUSION: Using different microsurgical patterns according to location of glioma, maximal resection of tumor may achieve with protection of neurological function.

[Individualized therapy and outcomes of microsurgery, radiotherapy, and chemotherapy for astrocytoma].

BACKGROUND & OBJECTIVE: Astrocytomas, constitute about 75% of neuroepithelial tumors, is one of the most common primary tumors in central nervous system with fairly high incidence and poor prognosis. Individualized multimodality is the hope for improving prognosis of patients with astrocytoma. This study was designed to investigate the efficiency of individualized treatment of microsurgery, radiotherapy, and chemotherapy for 62 patients with astrocytoma. METHODS: Sixty-two patients with astrocytoma in study group were treated with individualized multimodality of microsurgery, postoperative radiotherapy, and/or postoperative chemotherapy according to in vitro sensitivity assay. After microsurgery, 59 patients accepted radiotherapy, 46 patients received chemotherapy. Fifty patients with astrocytoma in control group were treated with conventional treatment of surgery, chemotherapy, and radiotherapy. After surgery, 31 patients received radiotherapy following by BCNU chemotherapy, while 19 patients accepted BCNU chemotherapy following radiotherapy. Pathologic diagnosis of patients in study group were 19 cases of grade, 32 cases of grade III, and 11 cases of grade IV; in control group were 13 cases of grade II, 28 cases of grade III, and 9 cases of grade IV. Mean follow-up time were 25.8 months, and the outcome was evaluated by MRI, KPS, and survival rate. RESULTS: Tumor total resection rate in study group was 67.7%, while that in control group was 58.0%. There was no significant difference of KPS and survival rate in patients with low-grade astrocytoma between 2 groups, while the outcome of patients with malignant astrocytoma was significantly improved by individualized treatment. In study group, 2-year expectant survival rate of patients with astrocytoma of grade III, and grade IV were 93.7%, and 36.3%, while in control group were 67.5%, and 22.2% (P< 0.05). In glioblastoma patients, median survival time of study group was 18.68 months, while that of control group was 12.83 months (P< 0.01). CONCLUSION: Individualized microsurgery may improve the total resection of astrocytoma, and benefit to postoperative treatment.Individualized radiotherapy/chemotherapy may prevent patients from some complications. Individualized management may improve prognosis of patients with astrocytoma, particularly malignant astrocytoma.