Human Glioma Proliferation Research Articles

Comprehensive analysis of EphA2 in pan-cancer: A prognostic biomarker associated with cancer immunity.

Several studies have reported a significant relationship between Ephrin receptor A2 (EphA2) and malignant progression in numerous cancers. However, there is a lack of comprehensive pan-cancer analysis on the prognostic value, mutation status, methylation landscape, and potential immunological function of EphA2. Using The Cancer Genome Atlas, Genotype Tissue Expression Database and GEO data, we analysed the differences in EphA2 expression between normal and tumour tissues and the effects of EphA2 on the prognosis of different tumours. Furthermore, using GSCALite, cBioPortal, TISDB, ULCLAN and TIMER 2.0 databases or platforms, we comprehensively analysed the potential oncogenic mechanisms or manifestations of EphA2 in 33 different tumour types, including tumour mutation status, DNA methylation status and immune cell infiltration. The correlation of EphA2 with immune checkpoints, tumour mutational burden, DNA microsatellite instability and DNA repair genes was also calculated. Finally, the effects of EphA2 inhibitors on the proliferation of human glioma and lung cancer cells were verified in cellular experiments. EphA2 is differentially expressed in different tumours, and patients with overexpression have poorer overall survival. In addition, gene mutations, gene copy number variation and DNA/RNA methylation of EphA2 have been identified in various tumours. Moreover, EphA2 is positively associated with immune infiltration involving macrophages and CD8+ T cells. Further, EphA2 mRNA expression is significantly associated with immune checkpoint in various cancers, especially programmed death-ligand 1. Finally, the EphA2 inhibitor ALW-II-41-27 shows potent anti-tumour activity. Our first pan-cancer study of EphA2 provides insight into the prognostic and immunological roles of EphA2 in different tumours, suggesting that EphA2 might be a potential biomarker for poor prognosis and immune infiltration in cancer.

Berberine Suppressed the Progression of Human Glioma Cells by Inhibiting the TGF-β1/SMAD2/3 Signaling Pathway.

Background:Previous studies have shown that berberine can inhibit glioma progression, although the underlying molecular mechanisms needed to be explored further. The aim of this study was to evaluate the suppressive effects of berberine on human glioma cells, and identify the underlying signaling pathways.Material and Methods:The cytotoxic effect of different concentrations of berberine against normal human glial cells (HEB) and 4 glioma cell lines was evaluated by the CCK-8 assay. Apoptosis was assayed by flow cytometry. In vitro migration and invasion were analyzed by the wound healing and transwell assays. The expression levels of specific proteins were measured by western blotting and ELISA.Results:Berberine significantly inhibited the proliferation of human glioma U-87 cells, and induced apoptosis in the U-87 and LN229 cells by downregulating Bcl-2, and upregulating Bax and caspase-3. In addition, berberine also inhibited migration and invasion of the glioma cells. Furthermore, berberine exerted its effects on the proliferation, migration, invasion, and apoptosis of glioma cells by inhibiting the TGF-β1/SMAD2/3 signaling pathway, and exogenous TGF-β abrogated the pro-apoptotic and anti-oncogenic effects of berberine.Conclusions:Berberine inhibits glioma progression by targeting the TGF-β1/SMAD2/3 signaling pathway.

Abstract 1382: Targeting Akt signaling pathway potentiates the antitumor effect of Tumor Treating Fields (TTFields) in vitro

Abstract Introduction Tumor Treating Fields (TTFields) therapy is a clinically applied anti-neoplastic treatment modality, approved for the treatment of glioblastoma and malignant pleural mesothelioma. TTFields are low intensity (1-3 V/cm) alternating electric fields within the intermediate frequency range (100-300 kHz), that are applied loco-regionally and non-invasively to the tumor site. Although TTFields therapy has demonstrated improved progression free survival and overall survival, tumor recurrence still occurs in some patients. To evaluate the cellular mechanisms of treatment resistance to TTFields, we analyzed changes in signaling pathway mediators in treated human glioma (U-87 MG) and ovarian (A2780) cancer cell lines. Also, we examined the in vitro efficacy of TTFields in combination with therapies that target molecular candidates that may confer resistance to TTFields. Methods To establish TTFields resistant glioma and ovarian cancer cell lines in vitro, 2 approaches were tested: 1) cyclic repetitions, where TTFields treatment was repeatedly applied for 72 hours with 24 hours breaks between treatment cycles; and 2) continuous, long-duration application of TTFields (1 or 2 weeks, depending on the cancer cell line type) without treatment breaks. Luminex assay followed by Western blot analysis were used to study changes in signaling pathways following TTFields treatment. Finally, we examined the in vitro efficacy of continuous, long-duration application of TTFields in combination with BGT226 (a phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) dual inhibitor). Results Application of TTFields using cyclic repetition significantly decreased proliferation of human glioma and ovarian cancer cells, whereas cells treated using continuous, long-duration application of TTFields showed reduced sensitivity to TTFields. Luminex analysis clearly showed activation of the PI3K/mTOR/AKT signaling pathway in response to TTFields treatment. To clarify the importance of this signaling pathway on regulating treatment resistance to TTFields, we examined the effect of TTFields, alone and in combination, with a PI3K/mTOR inhibitor (BGT226) on cancer cell proliferation, apoptosis, and activation of AKT. While long-duration application of TTFields led to Akt activation, TTFields in combination with BGT226 resulted in reduction of p-AKT S473, with a corresponding blockade of proliferation, induction of apoptosis, and decrease in the clonogenic potential. Conclusions We propose here a new mechanism of resistance to prolonged TTFields treatment mediated by the PI3K/mTOR/AKT signaling pathway in glioma and ovarian cancer cells. We demonstrate that combination therapy of TTFields and a targeted PI3K/mTOR dual inhibitor (BGT226) inhibited AKT S473 phosphorylation and sensitized cancer cells to “long-duration” TTFields application. Citation Format: Anat Klein-Goldberg, Tali Voloshin, Efrat Zemer-Tov, Rom Paz, Lilach Koren, Alexandra Volodin, Boris Brant, Moshe Giladi, Uri Weinberg, Yoram Palti. Targeting Akt signaling pathway potentiates the antitumor effect of Tumor Treating Fields (TTFields) in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1382.

MT1 and MT2 melatonin receptors play opposite roles in brain cancer progression.

Primary brain tumors remain among the deadliest of all cancers. Glioma grade IV (glioblastoma), the most common and malignant type of brain cancer, is associated with a 5-year survival rate of < 5%. Melatonin has been widely reported as an anticancer molecule, and we have recently demonstrated that the ability of gliomas to synthesize and accumulate this indolamine in the surrounding microenvironment negatively correlates with tumor malignancy. However, our understanding of the specific effects mediated through the activation of melatonin membrane receptors remains limited. Thus, here we investigated the specific roles of MT1 and MT2 in gliomas and medulloblastomas. Using the MT2 antagonist DH97, we showed that MT1 activation has a negative impact on the proliferation of human glioma and medulloblastoma cell lines, while MT2 activation has an opposite effect. Accordingly, gliomas have a decreased mRNA expression of MT1 (also known as MTNR1A) and an increased mRNA expression of MT2 (also known as MTNR1B) compared to the normal brain cortex. The MT1/MT2 expression ratio negatively correlates with the expression of cell cycle-related genes and is a positive prognostic factor in gliomas. Notably, we showed that functional selective drugs that simultaneously activate MT1 and inhibit MT2 exert robust anti-tumor effects in vitro and in vivo, downregulating the expression of cell cycle and energy metabolism genes in glioma stem-like cells. Overall, we provided the first evidence regarding the differential roles of MT1 and MT2 in brain tumor progression, highlighting their relevance as druggable targets. KEY MESSAGES: • MT1 impairs while MT2 promotes the proliferation of glioma and medulloblastoma cell lines. • Gliomas have a decreased expression of MT1 and an increased expression of MT2 compared to normal brain cortex. • Tumors with a high MT1/MT2 expression ratio have significantly better survival rates. • Functional selective drugs that simultaneously activate MT1 and inhibit MT2 downregulate the expression of cell cycle and energy metabolism genes in glioma stem-like cells and exert robust anti-tumor effects in vivo.

MicroRNA-585 inhibits human glioma cell proliferation by directly targeting MDM2

BackgroundMicroRNAs (miRNAs) are important regulators for cancer cell proliferation. miR-585 has been shown to inhibit the proliferation of several types of cancer, however, little is known about its role in human glioma cells.MethodsmiR-585 levels in human glioma clinical samples and cell lines were examined by quantitative real-time PCR (qRT-PCR) analysis. Cell proliferation was measured by Cell Counting Kit-8 (CCK-8) and EdU incorporation assays in vitro. For in vivo investigations, U251 cells were intracranially inoculated in BALB/c nude mice and xenografted tumors were visualized by magnetic resonance imaging (MRI).ResultsmiR-585 expression is downregulated in human glioma tissues and cell lines compared with non-cancerous counterparts. Additionally, miR-585 overexpression inhibits and its knockdown promotes human glioma cell proliferation in vitro. Moreover, miR-585 overexpression also inhibits the growth of glioma xenografts in vivo, suggesting that miR-585 may act as a tumor suppressor to inhibit the proliferation of human glioma. Furthermore, miR-585 directly targets and decreases the expression of oncoprotein murine double minute 2 (MDM2). More importantly, the restoration of MDM2 via enforced overexpression markedly rescues miR-585 inhibitory effect on human glioma cell proliferation, thus demonstrating that targeting MDM2 is a critical mechanism by which miR-585 inhibits human glioma cell proliferation.ConclusionsOur study unveils the anti-proliferative role of miR-585 in human glioma cells, and also implicates its potential application in clinical therapy.

CADM2 inhibits human glioma proliferation, migration and invasion.

Malignant glioma is one of the most common malignant tumors in the brain parenchyma with a poor prognosis. Cell adhesion molecules (CADMs) immunoglobulin super family is involved in the maintenance of cell adhesion, polarity and tumor suppression. However, the role and mechanisms of CADM2 in human glioma have yet to be elucidated. Therefore, the present study evaluated the expression level of CADM2 and demonstrated that CADM2 was markedly downregulated in human glioma tissues compared with normal brain tissue and glioma cell lines, and the CADM2 expression level was significantly decreased in high‑grade glioma tissues. Overexpression of CADM2 inhibited the proliferation of glioma cell proliferation in vitro and in vivo. CADM2 also inhibited the migration and invasion of U87 and U251 cells. Furthermore, overexpression of CADM2 induced a significant decrease in the expression of G1/S transition key regulators, cyclin D1, cyclin E, cyclin‑dependent kinase (CDK)2 and CDK4. Additionally, CADM2 expression was associated with alterations in epithelial‑mesenchymal transition (EMT) markers, including E‑cadherin and β‑catenin. Taken together, the results of the present study demonstrated that CADM2 inhibits glioma tumorigenesis by regulating the cell cycle and the EMT process, suggesting that CADM2 may be a novel potential therapeutic target in human glioma.

MicroRNA-124a suppresses PHF19 over-expression, EZH2 hyper-activation, and aberrant cell proliferation in human glioma

Enhancer of Zeste 2 (EZH2) is the key enzymatic factor in Polycomb Repressive Complex 2 (PRC2), a transcriptional repressor which contributes to oncogenesis. Recent research has revealed the key role of aberrant EZH2 hyper-activity in human gliomas. Here, we examined the role of the lesser-known PRC2-associated PHD Finger Protein 19 (PHF19) in human glioma. We found that PHF19 transcript and protein levels were significantly elevated in human glioma tumors, which was negatively associated with expression of the anti-PHF19 microRNA miR-124a. miR-124a over-expression in the A172 and U251MG glioma cell lines and patient glioma cells suppressed PHF19 expression, EZH2 activation, and cell proliferation. However, miR-124a did not suppress cell proliferation with PHF19 silencing or mutation. Knockdown of PHF19 suppressed EZH2 phosphorylation and proliferation of glioma cells. Co-immunoprecipitation confirmed that PHF19 forms the PRC2 with EZH2, EED, and SUZ12. In a nude murine model, subcutaneous and orthotopic xenograft tumor growth was significantly inhibited by miRNA-124a or PHF19 shRNA. In conclusion, miR-124a suppresses PHF19 over-expression, EZH2 hyper-activation, and aberrant glioma cell proliferation. Targeting PHF19 via miR-124a agomir therapy may block aberrant EZH2 hyper-activity in these tumors.

CacyBP/SIP inhibits the migration and invasion behaviors of glioblastoma cells through activating Siah1 mediated ubiquitination and degradation of cytoplasmic p27

Calcyclin-binding protein or Siah-1-interacting protein (CacyBP/SIP) has been reported to be up-regulated and plays an important role in promoting cell proliferation in human glioma. However, the effect of CacyBP/SIP on glioma cell motility is still unclear. Here, to our surprise, CacyBP/SIP was found to inhibit the migration and invasion of glioma cells U251 and U87. Silencing of CacyBP/SIP significantly promoted the migration and invasion behaviors of glioma cells. On the contrary, overexpression of CacyBP/SIP obviously suppressed them. Further investigation indicated that silencing of CacyBP/SIP significantly reduced the interaction between Siah1 and cytoplasmic p27, which in turn attenuated the ubiquitination and degradation of cytoplasmic p27. In contrast, overexpression of CacyBP/SIP promoted the interaction between Siah1 and cytoplasmic p27, which in turn increased the ubiquitination and degradation of cytoplasmic p27. Importantly, the degradation of p27 could be blocked by Siah1 knockdown. Finally, we found that CacyBP/SIP was reversely related to cytoplasmic p27 in human normal brain tissues and glioma tissues. Taken together, these results suggest that CacyBP/SIP plays an important role in inhibiting glioma cell migration and invasion through promoting the degradation of cytoplasmic p27.

CD164 regulates proliferation and apoptosis by targeting PTEN in human glioma.

Cluster of differentiation 164 (CD164), a sialomucin, has been demonstrated to be involved in the regulation of proliferation, apoptosis, adhesion and differentiation in multiple cancers. CD164 is regarded to be a potential promotor of tumor growth. However, the involvement of CD164 in human glioma proliferation and apoptosis remains unknown. The aim of the present study was to investigate the expression and oncogenic function of CD164 in normal human astrocytes (NHA) and glioma cells in vitro and in vivo. The results of the present study demonstrated that CD164 mRNA and protein levels were significantly increased in human glioma cell lines and tissue samples. CD164 overexpression promoted the proliferation of NHA in vitro, and its tumorigenic effect was confirmed in a murine xenograft model. Knockdown of CD164 inhibited cell proliferation and promoted apoptosis of the U87 human glioma cell line in vitro and in vivo. In addition, knockdown of CD164 was demonstrated to upregulate the Bax/Bcl2 ratio and phosphatase and tensin homolog (PTEN) expression, reduce protein kinase B (AKT) phosphorylation and promote the expression of p53 in U87 cells. The results suggest that CD164 expression may have affected the proliferation and apoptosis of human glioma cells via the PTEN/phosphoinositide 3-kinase/AKT pathway, and may therefore present a potential target for the diagnosis and treatment of glioma.

Karyopherinβ1 regulates proliferation of human glioma cells via Wnt/β-catenin pathway

Karyopherinβ1 (KPNB1), one of the cytosolic factors involved in the selective protein transport across nucleus, docked at nuclear pore complex and transported through nuclear envelope in an ATP-dependent style, assisting proteins to be recognized as import substrates. It has been reported to be bound up with the origination and progress of lung cancer, cervical cancer, head and neck cancer and hepatocellular carcinoma. In current study, we demonstrated for the first time that the role of KPNB1 in human glioma. KPNB1 was over-expressed as the well-known trend of Ki-67(p < 0.01) and tightly closed to poor prognosis, as an independent prognostic factor. In vitro, up-regulation of KPNB1 was accompanied by certain rising levels of proliferation markers, employing U251 and U87MG cells as serum-starve models. Silencing KPNB1 in U251 and U87MG led to G1 phase arrested directly via flow cytometry analysis. In the nucleus of KPNB1-depletion cell models, the decreasing expression of KPNB1 and β-catenin was detected respectively, which indicated that KPNB1 functioned via β-catenin signal. Besides, the interaction between KPNB1 and β-catenin was proved clearly by immunoprecipitation. Taken together, it showed that KPNB1 might enhance human glioma proliferation via Wnt/β-Catenin Pathway.

Protein phosphatase 1γ regulates the proliferation of human glioma via the NF-κB pathway.

Protein phosphatase 1γ (PP1γ), a member of mammalian protein phosphatases, serine/threonine phosphatases, catalyzes the majority of protein dephosphorylation events and regulates diverse cellular processes, such as neuronal signaling, muscle contraction, glycogen synthesis, and cell proliferation. However, its expression and potential functions in human glioma is unclear. In this study, we detected the high expression of PP1γ and phosphorylated p65 (p-p65) in human glioma tissues. Besides, we demonstrated that upregulation of PP1γ was tightly related to poor 5-year survival via systemic statistical analysis. Employing serum-starved and re-feeding models of U251 and U87MG, we observed the increasing expression of PP1γ and p-p65 were accompanied by the cell proliferation markers cyclin D1 and proliferating cell nuclear antigen (PCNA). Employing depletion-PP1γ models, we found downregulated PP1γ and p-p65 compared with upregulated IκBα, which indicates the inhibition of NF-κB pathway, and flow cytometry analysis confirmed the weakened cell proliferation. Moreover, we found that the translocation of p65 into the nucleus was impaired. Collectively, we identified the positive correlation between upregulation of PP1γ and human glioma cell proliferation and that knock-down of PP1γ alleviated the glioma proliferation by reducing p65 transportation into the nucleus. The results showed that PP1γ could accelerate human glioma proliferation via the NF-κB pathway.

Nucleostemin promotes the proliferation of human glioma via Wnt/β-Catenin pathway.

Nucleostemin, nucleolar guanosine triphosphate (GTP)-binding protein 3, is a member of the MMR1/HSR1 GTP-binding protein family. The important roles of nucleostemin in self-renewal, cell cycle regulation, apoptosis, and cell proliferation of various cancer types as been shown. Nevertheless, its expression and potential functions in human glioma is still unclear. In the present study, we demonstrated that up-regulation of nucleostemin was tightly related to poor 5-year-survival ratios. In serum-starved and re-feeding models of U251 and U373MG, we observed the rising expression of nucleostemin and p-β-Catenin (p-Tyr645) were accompanied with cell proliferation markers (cyclin D1 and proliferating cell nuclear antigen (PCNA)). Employing nucleostemin-depletion models, we found down-regulated nucleostemin and p-β-Catenin. The flow cytometry analysis proved the weakened cell proliferation. Moreover, we detected the translocation of β-Catenin into the nucleus was impaired, meaning the inhibition of the Wnt/β-Catenin pathway. Taken together, we identified a positive correlation between up-regulation of nucleostemin and human glioma cell proliferation and that knocking-down nucleostemin alleviated glioma proliferation by reducing β-Catenin transportation into the nucleus. All results suggested that nucleostemin might accelerate human glioma proliferation via the Wnt/β-Catenin pathway.

Eukaryotic translation initiation factor 3, subunit C is overexpressed and promotes cell proliferation in human glioma U-87 MG cells.

Disrupted protein translation is prevalent in tumours. Eukaryotic translation initiation factors (eIFs) were found to play an important role in various tumours. However, the involvement of eIFs in glioma remains to be elucidated. The present study explored the expression and the role of eIF 3, subunit C (eIF3c) in human glioma. The expression of eIF3c in glioma tissues was evaluated by immunohistochemistry. The impact of eIF3c inhibition on U-87 MG was explored in vitro and in vivo by lentivirus-mediated siRNA targeting eIF3c. The results revealed that overexpression of eIF3c was present in glioma tissues. Knockdown of eIF3c significantly impaired cell proliferation and colony formation, further induced cell cycle arrest and apoptosis in the U-87 MG cell line. Furthermore, tumoursphere formation in the U-87 MG glioma xenograft model was blocked by eIF3c knockdown. The involvement of eIF3c in the tumorigenesis of glioma was confirmed, suggesting eIF3c may be a promising therapy target in human glioma.

Overexpression of N-myc downstream-regulated gene 1 inhibits human glioma proliferation and invasion via phosphoinositide 3-kinase/AKT pathways.

N-myc downstream-regulated gene 1 (NDRG1) was previously shown to exhibit low expression in glioma tissue as compared with that in normal brain tissue; however, the role of NDRG1 in human glioma cells has remained to be elucidated. The present study used the U87 MG and SHG-44 human glioma cell lines as well as the normal human astrocyte cell line 1800, which are known to have differential NDRG1 expression. Small interfering (si)RNA targeting NDRG1, and NDRG1 overexpression vectors were transfected into the SHG-44 and U87 MG glioma cells, respectively. Cell proliferation, invasion, apoptosis and cell cycle arrest were subsequently examined by MTT assay, transwell chamber assay, flow cytometry and western blot analysis, respectively. Furthermore, a subcutaneous tumor mouse model was used to investigate the effects of NDRG1 on the growth of glioma cells in vivo. Overexpression of NDRG1 was shown to inhibit cell proliferation and invasion, and induce apoptosis in the U87 MG glioma cells, whereas NDRG1 downregulation increased proliferation, suppressed apoptosis and promoted invasion of the SHG-44 glioma cells. In addition, in the subcutaneous tumor mouse model, overexpression of NDRG1 in U-87 MG cells suppressed tumorigenicity in vivo. The findings of the present study indicated that NDRG1 is required for the inhibition of gliomagenesis; therefore, targeting NDRG1 and its downstream targets may represent novel therapies for the treatment of glioma.

Saw Palmetto Extract Inhibits Metastasis and Antiangiogenesis through STAT3 Signal Pathway in Glioma Cell.

Signal transducer and activator of transcription factor 3 (STAT3) plays an important role in the proliferation and angiogenesis in human glioma. Previous research indicated that saw palmetto extract markedly inhibited the proliferation of human glioma cells through STAT3 signal pathway. But its effect on tumor metastasis and antiangiogenesis is not clear. This study is to further clear the impact of saw palmetto extract on glioma cell metastasis, antiangiogenesis, and its mechanism. TUNEL assay indicated that the apoptotic cells in the saw palmetto treated group are higher than that in the control group (p < 0.05). The apoptosis related protein is detected and the results revealed that saw palmetto extract inhibits the proliferation of human glioma. Meanwhile pSTAT3 is lower in the experimental group and CD34 is also inhibited in the saw palmetto treated group. This means that saw palmetto extract could inhibit the angiogenesis in glioma. We found that saw palmetto extract was an important phytotherapeutic drug against the human glioma through STAT3 signal pathway. Saw palmetto extract may be useful as an adjunctive therapeutic agent for treatment of individuals with glioma and other types of cancer in which STAT3 signaling is activated.

P2X7 receptors are a potential novel target for anti-glioma therapies

Human gliomas pose significant morbidity and mortality to those afflicted by them, and currently there are no curative treatment modalities available for these highly invasive tumours. With the approval from the human ethics committee, patients diagnosed with brain tumour (glioma) were recruited for this study. At the time of surgical resection, freshly resected tumour as well as ‘peri-tumour’ tissue were taken directly from theatre to the laboratory and were successfully cultured. Confocal fluorescence microscopy techniques and immunohistochemistry were used for characterization of human glioma cultures. Dye uptake experiments and confocal microscopy were utilized for P2X7 receptor (P2X7R) pore activity. We reveal human glioma cultures to contain microglia in close association with glioma (tumour) cells. Both glioma cells and microglia were found to express the purinergic, ATP sensing, P2X7R. P2X7R protein expression was increased in microglia derived from tumour when compared to ‘peri-tumour’ tissue. The pore capacity of P2X7R in tumour-associated microglia was functional, as evidenced by dye uptake experiments. Importantly, inhibition of P2X7R with the synthetic antagonist, brilliant blue G (BBG) resulted in a significant decrease in the number of glioma cells in culture. P2X7R was found to be over-expressed in grade IV human gliomas and its pore capacity was functional. Antagonism of P2X7R with BBG resulted in a decrease in tumour cell number. This identifies P2X7R as a promising therapeutic target to combat human glioma proliferation.

Expression of PDGF-B and methylation levels of its gene promoter in human gliomas

Objective To investigate the role of platelet-derived growth factor B (PDGF-B) expression levels and the methylation levels of its gene promoter on proliferation of human gliomas.Methods The expressions of PDGF-B,p-Smad2 and Ki-67 were determined by immunohistochemistry in 54 human glioma specimens.And the methylation levels of PDGF-B gene promoter were determined using pyrosequencing.Results (1) The expression levels of PDGF-B increased with the pathologic grades elevated (P ＜0.05).(2) There was a positive and significant correlation between the expression levels of PDGF-Band Ki-67 as well as p-Smad2 (r =0.839,P ＜0.001) (r =0.802,P ＜0.001),respectively.And an inverse and significant correlation was found between the expression levels of PDGF-B and its gene promoter methylation (r =-0.817,P ＜0.001).(3) The methylation levels of PDGF-B gene promoter were significantly higher in low grade gliomas (WHO Ⅰ Ⅱ) than those in high grade gliomas (WHO Ⅲ Ⅳ) (P =0.001).Conclusions The expression levels of PDGF-B and its gene promoter methylation play an important role in predicting the malignancy and proliferation of human gliomas. Key words: Glioma; Gene Methylation; Pyrosequencing; Platelet-derived growth factov B

A phase II and pharmacodynamic trial of RO4929097 for patients with recurrent/progressive glioblastoma.

TPS135 Background: Patients with recurrent glioblastoma (rGBM) have a 6-month progression-free survival (PFS6) of only 10-15%. Cancer stem-like cells (CSCs) are a subset of cells that are capable of self renewal and differentiation within a tumor. These properties are felt to be a major cause of resistance to chemotherapy and radiotherapy. Furthermore, CSCs promote tumor angiogenesis. Therefore, CSCs are an attractive target for therapy of GBM. Proliferation of CSCs occurs via several pathways. One of the major signaling pathways is Notch. Elevation of Notch signaling imparts a tumor growth advantage by keeping tumor cells in a stem cell-like proliferative state. Expression of Notch is critical for survival and proliferation of human gliomas. Gamma secretase (GS) cleaves the Notch receptor as part of normal Notch function and is thus a critical enzyme in the Notch pathway. Therefore, disruption of the Notch pathway by inhibition of GS is a logical treatment strategy for patients with GBM. RO4929097 is an oral small molecule inhibitor of GS. This phase II and pharmacodynamic study will assess the efficacy of RO4929097 against rGBM and will include biomarker assays on freshly resected GBM samples from patients receiving this agent. Methods: Two groups of adults with contrast-enhancing rGBMs and no prior GS inhibitor treatment will be eligible: Group A - 40 non-surgical patients who will receive RO4929097, 20 mg 3 days on/4 days off with a primary endpoint of PFS6 on a standard phase II design; and Group B- 20 patients who will receive drug before and after resection of rGBM. Group B patients must have tumor > 2.5 cm in diameter. These patients will receive drug pre-op: 10 mg/d x 6 days; and post-op: 20 mg 3 days on/4 days off until progression. Fresh tumor from Group B patients will be assayed for neurosphere generation, expression levels of Notch pathway components and downstream targets and survival of mice bearing fresh tumor tissue. The goal is to achieve a 25% reduction of neurosphere generation when compared to a contemporaneous group of rGBM patients. If successful, these studies will provide proof of principle that CSC-targeted drug therapy can cross the blood tumor barrier and can alter the molecular and functional aspects of CSCs.

CDC25A mRNA levels significantly correlate with Ki-67 expression in human glioma samples

Cell division cycle 25 (CDC25) phosphatases are cell-cycle regulatory proteins which are overexpressed in a significant number of human cancers. This study evaluated the role of CDC25 phosphatases in human glioma proliferation. Upregulation of CDC25A was observed in human glioma specimens and human glioma cell lines. Comparison of expression levels of CDC25A and CDC25B messenger ribonucleic acid (RNA) to Ki-67 labeling index in glioma tissues found that Ki-67 labeling index was significantly correlated with the expression of CDC25A, but not with that of CDC25B. Depletion of CDC25A by small interfering RNA and inhibition of CDC25 suppressed cell proliferation and induced apoptosis in glioma cell lines, indicating that CDC25A is a potential target for the development of new therapy for glioma.

Relationship of cyclooxygenase with vascularization and proliferation in human glioma

Objective Investigate the relationship of cyclooxygenase (COX-2) with vascularization and proliferation in human glioma. Methods The expression of COX-2 mRNA was detected in 67 cases of ghoma and 8 cases of normal brain specimens by using in situ hibridization method. Ki-67 and CD34 protein expression was assayed in 67 cases of ghoma and 8 cases of normal brain specimens by immunohistochemistry to investigate the vascularization and proliferation. Results The expression of COX mRNA was detected in glioma tissue and not in normal brain specimens. The expression of Ki-67 and CD34 was significantly higher in COX-2 positive specimens than in COX-2 negative specimens, and the expression of Ki-67 and CD34 was significantly higher in high-grade ghoma than low-grade ghoma and normal brain specimens. Conclusion Glioma cell proliferation and vascularization strongly connects with COX-2 gene. The study suggests that COX-2 gene may play an important role in human glioma cell proliferation and vascularization. Key words: Glioma; Vascular proliferation; Cyclooxygenase-2