Non-neoplastic Brain Tissues Research Articles

Comparison of microRNA expression levels between initial and recurrent glioblastoma specimens

Glioblastoma is the most frequent primary brain tumour in adults. Recent therapeutic advances increased patient's survival, but tumour recurrence inevitably occurs. The pathobiological mechanisms involved in glioblastoma recurrence are still unclear. MicroRNAs are small RNAs proposed o have important roles for cancer including proliferation, aggressiveness and metastases development. There exist only few data on the involvement of microRNAs in glioblastoma recurrence. We selected the following 7 microRNAs with potential relevance for glioblastoma pathobiology by means of a comprehensive literature search: microRNA-10b, microRNA-21, microRNA-181b, microRNA-181c, microRNA-195, microRNA-221 and microRNA-222. We further selected 15 primary glioblastoma patients, of whom formalin fixed and paraffin embedded tissue (FFPE) of the initial and recurrence surgery were available. All patients had received first line treatment consisting of postoperative combined radiochemotherapy with temozolomide (n = 15). Non-neoplastic brain tissue samples from 3 patients with temporal lobe epilepsy served as control. The expression of the microRNAs were analysed by RT-qPCR. These were correlated with each other and with clinical parameters. All microRNAs showed detectable levels of expressions in glioblastoma group, whereas microRNA-10b was not detectable in epilepsy patients. MicroRNAs except microRNA-21 showed significantly higher levels in epilepsy patients when compared to the levels of first resection of glioblastoma. Comparison of microRNA levels between first and second resections revealed no significant change. Cox regression analyses showed no significant association of microRNA expression levels in the tumor tissue with progression free survival times. Expression levels of microRNA-10b, microRNA-21, microRNA-181b, microRNA-181c, microRNA-195, microRNA-221 and microRNA-222 do not differ significantly between initial and recurrent glioblastoma.

Involvement of estrogen receptor β5 in the progression of glioma

Emerging evidence suggests a decline of ERβ expression in various peripheral cancers. ERβ has been proposed as a cancer brake that inhibits tumor proliferation. In the current study, we have identified ERβ5 as the predominant isoform of ERβ in human glioma and its expression was significantly increased in human glioma as compared with non-neoplastic brain tissue. Hypoxia and activation of hypoxia inducible factor (HIF) increased ERβ transcription in U87 cells, suggesting elevated ERβ expression in glioma might be induced by the hypoxic stress in the tumor. Over-expression of either ERβ1 or ERβ5 increased PTEN expression and inhibited activation of the PI3K/AKT/mTOR pathway. In addition, ERβ5 inhibited the MAPK/ERK pathway. In U87 cells, ERβ1 and ERβ5 inhibit cell proliferation and reduced cells in the S+G2/M phase. Our findings suggest hypoxia induced ERβ5 expression in glioma as a self-protective mechanism against tumor proliferation and that ERβ5 might serve as a therapeutic target for the treatment of glioma.

WEE1 Kinase Inhibition Enhances the Radiation Response of Diffuse Intrinsic Pontine Gliomas

Diffuse intrinsic pontine glioma (DIPG) is a fatal pediatric disease. Thus far, no therapeutic agent has proven beneficial in the treatment of this malignancy. Therefore, conventional DNA-damaging radiotherapy remains the standard treatment, providing transient neurologic improvement without improving the probability of overall survival. During radiotherapy, WEE1 kinase controls the G(2) cell-cycle checkpoint, allowing for repair of irradiation (IR)-induced DNA damage. Here, we show that WEE1 kinase is one of the highest overexpressed kinases in primary DIPG tissues compared with matching non-neoplastic brain tissues. Inhibition of WEE1 by MK-1775 treatment of DIPG cells inhibited the IR-induced WEE1-mediated phosphorylation of CDC2, resulting in reduced G(2)-M arrest and decreased cell viability. Finally, we show that MK-1775 enhances the radiation response of E98-Fluc-mCherry DIPG mouse xenografts. Altogether, these results show that inhibition of WEE1 kinase in conjunction with radiotherapy holds potential as a therapeutic approach for the treatment of DIPG.

Characterization of microglia/macrophages in gliomas developed in S‐100β‐v‐erbB transgenic rats

Glioma-infiltrating microglia/macrophages are referred to as tumor-associated macrophages (TAMs). Transgenic (TG) rats expressing v-erbB, which is a viral form of the epidermal growth factor receptor, under transcriptional regulation by the S100-β promoter, develop brain tumors. This study was designed to clarify the pathological characteristics of TAMs in these experimental tumors. We carried out immunohistochemical and morphometrical analyses of microglia/macrophages in brain tumors (5 malignant glioma, 4 anaplastic oligodendroglioma, 4 astrocytoma) that developed in TG rats. TAMs with ionized calcium-binding adaptor molecule 1 (Iba1) positivity and morphology of activated, non-phagocytic microglia increased within and around the tumors in malignant gliomas and anaplastic astrocytomas. The Iba1-positive TAMs of the tumor core were significantly more activated than Iba1-positive microglia of non-neoplastic brain tissue in intraparenchymal anaplastic oligodendrogliomas. Iba1 expression showed a significant positive correlation to Ki-67 expression in all the gliomas. Most TAMs showed no or little expression against CD68, CD163 or CD204, although CD204-positive TAMs were observed in necrosis as well as in the proliferating vascular wall. In conclusion, S-100β-v-erbB TG rats may serve as a useful animal model for further analysis of TAMs in terms of tumor cell proliferation, microvascular proliferation and phagocytosis, and as a tool for therapeutic use in malignant gliomas, although it should be noted that the polarization of TAMs toward the M2 phenotype remains unclear.

Correlation of microrna-372 upregulation with poor prognosis in human glioma

MicroRNA-372 (miR-372) acts as either an oncogenic miRNA or an anti-oncomiR in various human malignancies. However, its roles in gliomas have not been elucidated. To address this problem, we here detected miR-372 expression in human gliomas and non-neoplastic brain tissues by real-time quantitative RT-PCR assay. The association of miR-372 expression with clinicopathological factors or prognosis of glioma patients was also statistically analyzed. As the results, miR-372 expression levels were significantly upregulated in glioma tissues compared to the corresponding non-neoplastic brain tissues (P<0.001). In addition, the high miR-372 expression was significantly associated with the advanced pathological grade (P=0.008) and the low Karnofsky performance score (KPS) of glioma patients (P=0.01). Moreover, the overall survival of patients with high miR-372 expression was dramatically shorter than those with low miR-372 expression (P<0.001). Furthermore, multivariate Cox regression analysis indicated that miR-372 expression was an independent prognostic factor for glioma patients (P=0.008). More importantly, subgroup analyses according to tumor pathological grade revealed that the cumulative overall survival of glioma patients with advanced pathological grades was significantly worse for high miR-372 expression group than for low miR-372 expression group (P<0.001), but no significant difference was found for patients with low pathological grades (P=0.08). Taken together, these data offer the convincing evidence for the first time that miR-372 may act as an oncogenic miRNA in gliomas and represent a potential regulator of aggressive development and a candidate prognostic marker for this malignancy, especially for advanced tumors with high pathological grades.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1707761328850011

Emerging Significance of Estrogen Receptor β in Gliomas

Primary brain tumors are heterogeneous group of intracranial lesions that are categorized into different subtypes based on their close morphology to their parental cell. Gliomas are the most common and deadliest tumors that accounts for ~70-80% of total brain tumors and the etiology of brain tumors is not completely understood [1-3]. Recent evidence suggests that the incidence of brain tumors is significantly higher in men than in women during the periods of active menstrual cycle suggesting the possible protective role of female sex hormones in the development of brain tumors [4-6]. Furthermore, a lower glioma incidence was reported for females who used exogenous hormones. The existence of a gender bias and the involvement of steroid hormones in the development of gliomas highlight the importance of this field in the glioma pathobiology. Estrogens are the steroid hormones that play a crucial role during development and differentiation of central nervous system [7,8], and locally synthesized estrogens play an essential role in neuroprotective functions [9]. The biological effects of estrogens are mediated through their cognate receptors: estrogen receptor alpha [ERα] and estrogen receptor beta [ERβ] [10]. ERβ has quite a different function than ERα and ERβ functions as a tissue-specific tumour suppressor with antiproliferative actions [10,11]. Several studies demonstrated that most of the gliomas express ERβ with negative or weak expression of ERα. ERβ is highly expressed in low-grade astrocytomas and non-neoplastic brain tissues. In contrast, most of the high-grade tumors express low ERβ expression and this lower ERβ expression correlates with histological malignancy and poor survival of patients [12-14]. Lower ERβ expression is significantly associated with higher expression of cytoplasmic BAG-1 [a coregulator of ER signalling] and worse clinical outcome [14]. Further, high expression of ERβ was an independent favourable prognostic factor [15].

Correlation of microRNA-375 downregulation with unfavorable clinical outcome of patients with glioma

Background and aimMicroRNA-375 (miR-375) is frequently demonstrated to be frequently dysregulated and functions as a tumor suppressor or an oncogene in different cancer types. However, its roles in human gliomas have not been reported. The aim of this study was to investigate the expression pattern and clinical significance of miR-375 in patients with gliomas. MethodsReal-time quantitative RT-PCR assay was performed to detect miR-375 expression in human gliomas and non-neoplastic brain tissues. Then, the association of miR-375 expression with clinicopathological factors and prognosis of glioma patients was also statistically analyzed. ResultsmiR-375 expression was significantly decreased on average in glioma tissues relative to non-neoplastic brain tissues (P<0.0001) with ascending pathological grade. Then, the low miR-375 expression in glioma tissues was significantly associated with advanced pathological grade (P=0.003) and low Karnofsky performance score (KPS, P=0.01). Moreover, both univariate and multivariate Cox regression analyses determined that loss of miR-375 expression effectively predicted the decreased overall survival in patients with gliomas. ConclusionsThese findings offer the first convinced evidence that the downregulation of miR-375 expression in human gliomas may play an inhibitory role during the tumor development. This miRNA might function as a candidate unfavorable prognostic marker for human gliomas.

Kinesin family member 14 is a candidate prognostic marker for outcome of glioma patients

Background & aim: Human kinesin superfamily proteins (KIFs) are a conserved class of microtubule-dependent molecular motor proteins with adenosine triphosphatase activity and motion characteristics. As a member of KIFs, KIF14 plays an important role in the regulation of cell cycle and mitotic progression. Deregulation of KIF14 has been found in several human malignancies and also has been demonstrated to be involved in tumor progression and related to patient survival. The aim of this study was to investigate the clinicopathological significance of KIF14 expression in glioma. Methods: Real-time quantitative RT-PCR assay was performed to detect KIF14 mRNA expression, and Western blot and immunohistochemistry analyses were performed to detect KIF14 protein expression in human gliomas and non-neoplastic brain tissues, respectively. Then, the association of KIF14 immunostaining with clinicopathological factors and prognosis of glioma patients was also statistically analyzed. Results: KIF14 mRNA and protein expression were respectively increased 5.5- and 4.2-fold on average in glioma tissues relative to non-neoplastic brain tissues (both P<0.001). Additionally, both KIF14 mRNA and protein expression increased with ascending pathological grade. Then, the high KIF14 immunostaining in glioma tissues was significantly associated with advanced pathological grade (P=0.008), low Karnofsky performance score (KPS) (P=0.02), high mitotic index (P=0.005) and Ki-67 index (P=0.008). Furthermore, both univariate and multivariate Cox regression analyses determined that KIF14 overexpression effectively predicted decreased overall survival in patients with gliomas. Conclusions: These findings offer the first convinced evidence that KIF14 expression in gliomas is tumor-specific and increased in more aggressive tumors. KIF14 might function as a candidate prognostic marker for human gliomas.

426P - Comparison of Microrna Expression Levels between Initial and Recurrent Glioblastoma Specimens

Glioblastoma is the most frequent primary brain tumour in adults. Recent therapeutic advances increased patient's survival, but tumour recurrence inevitably occurs. The pathobiological mechanisms involved in glioblastoma recurrence are still unclear. MicroRNAs are small RNAs proposed o have important roles for cancer including proliferation, aggressiveness and metastases development. There exist only few data on the involvement of microRNAs in glioblastoma recurrence. We selected the following 7 microRNAs with potential relevance for glioblastoma pathobiology by means of a comprehensive literature search: microRNA-10b, microRNA-21, microRNA-181b, microRNA-181c, microRNA-195, microRNA-221 and microRNA-222. We further selected 15 primary glioblastoma patients, of whom formalin fixed and paraffin embedded tissue (FFPE) of the initial and recurrence surgery were available. All patients had received first line treatment consisting of postoperative combined radiochemotherapy with temozolomide (n = 15). Non-neoplastic brain tissue samples from 3 patients with temporal lobe epilepsy served as control. The expression of the microRNAs were analysed by RT-qPCR. These were correlated with each other and with clinical parameters. All microRNAs showed detectable levels of expressions in glioblastoma group, whereas microRNA-10b was not detectable in epilepsy patients. MicroRNAs except microRNA-21 showed significantly higher levels in epilepsy patients when compared to the levels of first resection of glioblastoma. Comparison of microRNA levels between first and second resections revealed no significant change. Cox regression analyses showed no significant association of microRNA expression levels in the tumor tissue with progression free survival times. Expression levels of microRNA-10b, microRNA-21, microRNA-181b, microRNA-181c, microRNA-195, microRNA-221 and microRNA-222 do not differ significantly between initial and recurrent glioblastoma.

Overexpression of CCL20 and its receptor CCR6 predicts poor clinical prognosis in human gliomas

Recent studies have demonstrated that the chemokine CCL20 and its receptor CCR6 may be involved in tumorigenesis, tumor progression and metastatic spread of various human malignancies. The aim of this study was to investigate the clinicopathological significance and prognostic value of CCL20 and CCR6 expression in human malignant glioma. CCL20 and CCR6 expression in human gliomas and nonneoplastic brain tissues was measured by immunohistochemistry. The association of CCL20 and CCR6 expression with clinicopathological factors or prognosis in glioma patients was statistically analyzed. The expression levels of CCL20 and CCR6 proteins were both up-regulated in glioma tissues. There was a significantly positive correlation between the expression of the two markers (r = 0.88; P < 0.001). In addition, the overexpressions of CCL20 and CCR6 were both detected in high-grade glioma tissues compared with those in low-grade tissues and increased with ascending tumor World Health Organization (WHO) grades (P = 0.006 and 0.008, respectively). The increased expressions of CCL20 and CCR6 proteins were also significantly correlated with low Karnofsky performance score (both P = 0.01). Moreover, univariate analysis found that CCL20 expression (P = 0.002), CCR6 expression (P = 0.002) and CCL20/CCR6 co-expression (P < 0.001) were all significantly associated with poor prognosis. In particular, glioma patients with CCL20/CCR6 co-expression have the shortest overall survival. Multivariate analysis further identified the expression levels of CCL20 and CCR6 to be independent prognostic factors. Our data suggest for the first time that CCL20 and CCR6 might play an important role in the regulation of aggressiveness in human gliomas. The up-regulation of CCL20 and CCR6 might be closely associated with poor clinical outcome of patients with gliomas.

Co-expression of MMP-14 and MMP-19 predicts poor survival in human glioma

Matrix metalloproteinase (MMP)-14 and MMP-19 have been demonstrated to play an important role in the development of human gliomas. However, their prognostic values are not clear. The aim of this study was to investigate whether co-expression of MMP-14 and MMP-19 has prognostic relevance in human gliomas. Immunohistochemistry and western blot were used to investigate the expression of MMP-14 and MMP-19 proteins in 128 patients with gliomas. The expression levels of MMP-14 and MMP-19 proteins in glioma tissues were both significantly higher (both P < 0.001) than those in non-neoplastic brain tissues according to the immunohistochemistry analysis, which was confirmed by the western blot analysis. Additionally, the overexpression of either MMP-14 or MMP-19 was significantly associated with the advanced WHO grade (both P = 0.02), the low Karnofsky performance score (KPS) (P = 0.008 and 0.01, respectively) and the poor overall survival (both P = 0.01). Moreover, the Multivariate Cox proportional-hazards regression analysis revealed that the increased expressions of MMP-14 and MMP-19 were both independent prognostic factors for poor overall survival (both P = 0.02). Furthermore, the co-expression of MMP-14 and MMP-19 was additively and more significantly (P = 0.006) associated with adverse prognosis in patients with gliomas than respective expression of MMP-14 and MMP-19. These findings indicated for the first time that the co-expression of MMP-14 and MMP-19 is significantly correlated with prognosis in glioma patients, suggesting that the co-expression of these proteins may be used as both an early diagnostic and independent prognostic marker.

Oncogenic role of SOX9 expression in human malignant glioma

SOX9 belongs to the SOX (Sry-related high-mobility group box) family and acts as a transcription factor that plays a central role in the development and differentiation of multiple cell lineages. Recent studies have demonstrated that SOX9 is required for the carcinogenesis in several cancer types. The aim of this study was to investigate the clinicopathological significance of SOX9 expression in human malignant glioma. SOX9 mRNA expression was detected by real-time quantitative RT-PCR assay in glioma and nonneoplastic brain tissues. Then, the association of SOX9 mRNA expression with clinicopathological factors or prognosis of glioma patients was statistically analyzed. In addition, the small interfering RNA was used to knockdown SOX9 expression in a glioma cell line and to analyze the effects of SOX9 inhibition on cell growth, cell cycle and apoptosis of glioma cell line. The expression level of SOX9 mRNA in glioma tissues was significantly higher than that in corresponding nonneoplastic brain tissues (P < 0.001). In addition, a high level of SOX9 mRNA expression was significantly more common in glioma tissues with advanced WHO grade than those with low grade (P = 0.02). The increased expression of SOX9 mRNA was also significantly correlated with low Karnofsky performance score (P = 0.008). Meanwhile, the disease-free and overall survival rates of patients with high SOX9 mRNA expression were obviously lower than those of patients with low SOX9 mRNA expression (both P = 0.01). Multivariate analysis showed that high SOX9 mRNA expression was an independent prognostic factor for glioma patients (P = 0.02). Moreover, the down-regulation of SOX9 could inhibit the cell growth, induce the cell arrest in G2/M phase of cell cycle and enhance the apoptosis in glioma cells. Our data suggest for the first time that the over-expression of SOX9 mRNA is closely associated with poor clinical outcome of patients with malignant gliomas, and targeting SOX9 may be a novel therapeutic strategy for this tumor.

Oncogenic reg IV is a novel prognostic marker for glioma patient survival

AimThe aberrant expression of regenerating islet-derived family member, 4 (Reg IV) has been found in various human cancers. However, the roles of Reg IV gene and its encoding product in human glioma have not been clearly understood. Therefore, the aim of this study was to investigate the clinicopathological significance of Reg IV expression in glioma.MethodsReg IV mRNA and protein expression in human gliomas and non-neoplastic brain tissues were respectively detected by real-time quantitative RT-PCR assay, Western blot, and immunohistochemistry. The association of Reg IV immunostaining with clinicopathological factors and prognosis of glioma patients was also statistically analyzed.ResultsReg IV mRNA and protein expression levels in glioma tissues were both significantly higher than those in the corresponding non-neoplastic brain tissues (both P < 0.001). Additionally, the increased Reg IV immunostaining in glioma tissues was significantly associated with advanced pathological grade (P = 0.008). Reg IV protein up-regulation was also significantly correlated with low Karnofsky performance score (KPS) (P = 0.02). Moreover, the overall survival of patients with high Reg IV protein expression was dramatically shorter than those with low Reg IV protein expression (P < 0.001). Multivariate Cox regression analysis further confirmed that Reg IV expression was an independent prognostic factor for patients with gliomas (P = 0.008).ConclusionsThese convinced evidences suggest for the first time that Reg IV might accelerate disease progression and act as a candidate prognostic marker for gliomas.Virtual slidesThe virtual slide(s) for this article can be found here:http://www.diagnosticpathology.diagnomx.eu/vs/2145344361720706

Down-Regulation of Neogenin Accelerated Glioma Progression through Promoter Methylation and Its Overexpression in SHG-44 Induced Apoptosis

BackgroundDependence receptors have been proved to act as tumor suppressors in tumorigenesis. Neogenin, a DCC homologue, well known for its fundamental role in axon guidance and cellular differentiation, is also a dependence receptor functioning to control apoptosis. However, loss of neogenin has been reported in several kinds of cancers, but its role in glioma remains to be further investigated.Methodology/Principal FindingsWestern blot analysis showed that neogenin level was lower in glioma tissues than in their matching surrounding non-neoplastic tissues (n = 13, p<0.01). By immunohistochemical analysis of 69 primary and 16 paired initial and recurrent glioma sections, we found that the loss of neogenin did not only correlate negatively with glioma malignancy (n = 69, p<0.01), but also glioma recurrence (n = 16, p<0.05). Kaplan-Meier plot and Cox proportional hazards modelling showed that over-expressive neogenin could prolong the tumor latency (n = 69, p<0.001, 1187.6±162.6 days versus 687.4±254.2 days) and restrain high-grade glioma development (n = 69, p<0.01, HR: 0.264, 95% CI: 0.102 to 0.687). By Methylation specific polymerase chain reaction (MSP), we reported that neogenin promoter was methylated in 31.0% (9/29) gliomas, but absent in 3 kinds of glioma cell lines. Interestingly, the prevalence of methylation in high-grade gliomas was higher than low-grade gliomas and non-neoplastic brain tissues (n = 33, p<0.05) and overall methylation rate increased as glioma malignancy advanced. Furthermore, when cells were over-expressed by neogenin, the apoptotic rate in SHG-44 was increased to 39.7% compared with 8.1% in the blank control (p<0.01) and 9.3% in the negative control (p<0.01).Conclusions/SignificanceThese observations recapitulated the proposed role of neogenin as a tumor suppressor in gliomas and we suggest its down-regulation owing to promoter methylation is a selective advantage for glioma genesis, progression and recurrence. Furthermore, the induction of apoptosis in SHG-44 cells after overexpression of neogenin, indicated that neogenin could be a novel target for glioma therapy.

Tumor microRNA-335 expression is associated with poor prognosis in human glioma

MicroRNA-335 (miR-335), as a transcript of genomic region chromosome 7q32.2, acts as a tumor suppressor or tumor promoter in various human malignancies. Especially, it has been reportedly shown to be an oncogene in human glioma cell line in vitro, but its expression in human glioma tissues is not yet determined. The aim of this study was to investigate the clinical significance of miR-335 expression in glioma. MiR-335 expression in human gliomas and nonneoplastic brain tissues was measured by real-time quantitative RT-PCR assay. The association of miR-335 expression with clinicopathological factors and prognosis of glioma patients was statistically analyzed. The expression level of miR-335 in glioma tissues was significantly higher than that in corresponding nonneoplastic brain tissues (P < 0.001). In addition, high miR-335 expression was significantly associated with a higher WHO grade (P = 0.001). Survival analysis demonstrated that patients with high miR-335 expression tumors had significantly shorter survival times than those with low miR-335 expression tumors (P = 0.01) and that miR-335 was an independent prognostic factor (P = 0.02). Especially, subgroup analyses according to tumor histologic grade revealed that the mean survival time of patients with high grade (III-IV) was significantly worse for high miR-335 expression group than for low miR-335 expression group (P = 0.002), but no significant difference was found for patients with WHO grade I-II (P = 0.16). These results indicated that miR-335 expression was increased in human gliomas and was associated with advanced tumor progression. Furthermore, miR-335 expression was demonstrated for the first time to be an independent marker for predicting the clinical outcome of patients with gliomas.

Quantification, self-renewal, and genetic tracing of FL1+ tumor-initiating cells in a large cohort of human gliomas

Evidence has emerged that the initiation and growth of gliomas is sustained by a subpopulation of cancer-initiating cells (CICs). Because of the difficulty of using markers to tag CICs in gliomas, we have previously exploited more robust phenotypic characteristics, including a specific morphology and intrincic autofluorescence, to identify and isolate a subpopulation of glioma CICs, called FL1(+). The objective of this study was to further validate our method in a large cohort of human glioma and a mouse model of glioma. Seventy-four human gliomas of all grades and the GFAP-V(12)HA-ras B8 mouse model were analyzed for in vitro self-renewal capacity and their content of FL1(+). Nonneoplastic brain tissue and embryonic mouse brain were used as control. Genetic traceability along passages was assessed with microsatellite analysis. We found that FL1(+) cells from low-grade gliomas and from control nonneoplasic brain tissue show a lower level of autofluorescence and undergo a restricted number of cell divisions before dying in culture. In contrast, we found that FL1(+) cells derived from many but not all high-grade gliomas acquire high levels of autofluorescence and can be propagated in long-term cultures. Moreover, FL1(+) cells show a remarkable traceability over time in vitro and in vivo. Our results show that FL1(+) cells can be found in all specimens of a large cohort of human gliomas of different grades and in a model of genetically induced mouse glioma as well as nonneoplastic brain. However, their self-renewal capacity is variable and seems to be dependent on the tumor grade.

Elevated expression of chloride intracellular channel 1 is correlated with poor prognosis in human gliomas

BackgroundChloride intracellular channel 1 (CLIC1) is expressed ubiquitously in human tissues and is involved in the regulation of cell cycle, cell proliferation and differentiation. Recent studies have shown that CLIC1 is highly expressed in several human malignant tumors. However, its roles in human gliomas are still unclear. The aim of this study was to investigate the clinicopathological significance and prognostic value of CLIC1 expression in human gliomas.MethodsCLIC1 expression in human gliomas and nonneoplastic brain tissues was measured by real-time quantitative RT-PCR assay and immunohistochemistry. Its association with clinicopathological factors or prognosis in patients with gliomas was statistically analyzed.ResultsThe expression of CLIC1 at both mRNA and protein levels was significantly increased in high-grade (Grade III~IV) glioma tissues compared with that in low-grade (Grade I~II) and nonneoplastic brain tissues, and was up-regulated with ascending tumor World Health Organization (WHO) grades. The elevated expression of CLIC1 protein was also significantly correlated with low Karnofsky performance score (KPS) (P=0.008). Moreover, both univariate and multivariate analysis shown that high CLIC1 expression was significantly associated with poor prognosis in patients with gliomas (P<0.001 and P=0.01, respectively). In particular, the elevated CLIC1 expression also correlated with shorter overall survival in different glioma subgroups stratified according to the WHO grading.ConclusionsOur data provide the first evidence that CLIC1 expression might play an important role in the regulation of aggressiveness in human gliomas. The elevated expression of CLIC1 might represent a valuable prognostic marker for this disease.

Increased Expression of FAT10 is Correlated with Progression and Prognosis of Human Glioma

FAT10, as a small ubiquitin-like modifier, plays an important role in various cellular processes, including mitosis, immune response, and apoptosis, the dys-regulation of which may arise tumorigenesis. Therefore, the aim of this study was to examine the expression of FAT10 at gene and protein levels in glioma samples with different WHO grades and its association with survival. One hundred and twenty-eight glioma specimens and 10 non-neoplastic brain tissues were collected. Immunohistochemistry assay, quantitative real-time PCR and Western blot analysis were carried out to investigate the expression of FAT10. Kaplan-Meier method and Cox's proportional hazards model were used in survival analysis. Immunohistochemistry showed that FAT10 protein was over-expressed in glioma tissues. FAT10 mRNA and protein levels were both higher in glioma compared to control on real-time PCR and Western blot analysis (both P < 0.001). Additionally, its expression levels increase from grade I to grade IV glioma according to the results of real-time PCR, immunohistochemistry analysis and Western blot. Moreover, the survival rate of FAT10-positive patients was significantly lower than that of FAT10-negative patients (P < 0.001). We further confirmed that the increased expression of FAT10 was a significant and independent prognostic indicator in glioma by multivariate analysis (P < 0.001). Our data provides convincing evidence for the first time that the increased expression of FAT10 at gene and protein levels is correlated with poor outcome in patients with glioma. FAT10 may promote the aggressiveness of glioma and may be a potential prognosis predictor of glioma.

Downregulation of N-Myc downstream-regulated gene 4 influences patient survival in gliomas

N-Myc downstream-regulated gene 4 (NDRG4) plays important roles in cellular differentiation and neurite formation. It is required for cell cycle progression and survival in established glioblastoma cell lines and cancer stem cell-enriched cells. The aim of this study was to evaluate the correlation of NDRG4 expression with the clinicopathological features and prognosis in patients with gliomas. Immunohistochemistry and Western blot analysis were used to investigate the expression of NDRG4 protein, respectively, in 128 patients with gliomas. Immunohistochemistry showed that NDRG4 expression was significantly reduced in glioma relative to nonneoplastic brain tissues (P=0.008), and that its expression decreased with increasing glioma grade. These results were in line with the results of Western blot analysis. In addition, a non-parametric analysis revealed that the reduced NDRG4 expression was significantly correlated with a low Karnofsky performance score (P=0.01), frequent intra-tumor necrosis (P=0.03), and poor overall survival (P=0.01). Furthermore, multivariate analysis showed that NDRG4 expression (P=0.03) and intra-tumor necrosis (P=0.03) were two important independent prognostic factors identified by the Cox proportional hazard model. Our results provide convincing evidence for the first time that the expression of NDRG4 is downregulated in human gliomas. The glioma patients with lower NDRG4 expression have a poor prognosis.

Aberrant Expression of N-Methylpurine-DNA Glycosylase Influences Patient Survival in Malignant Gliomas

Aim. To examine the expression of N-methylpurine-DNA glycosylase (MPG) gene and protein in glioma samples with different WHO grades and its association with patients' survival. Methods. Immunohistochemistry assay, quantitative real-time PCR and Western blot analysis were carried out to investigate the expression of MPG gene and protein in 128 glioma and 10 non-neoplastic brain tissues. Results. MPG gene expression level in glioma tissues was significantly higher than that in non-neoplastic brain tissues (P < 0.001). Immunohistochemistry also showed that MPG protein was over-expressed in glioma tissues, which was consistent with the resutls of Western blot analysis. Additionally, the expression levels of MPG gene and protein both increase from grade I to grade IV glioma according to the results of real-time PCR, immunohistochemistry and western blot analysis. Moreover, the survival rate of MPG-positive patients was significantly lower than that of MPG-negative patients (P < 0.001). We further confirmed that the over-expression of MPG was a significant and independent prognostic indicator in glioma by multivariate analysis (P < 0.001). Conclusions. Our data showed the over-expression of MPG gene and protein in human gliomas, and also suggested for the first time that MPG be an unfavorable independent prognostic indicator for glioma patients.