GBM Cell Growth Research Articles

CBIO-09. ONCOGENIC ROLE OF NFIA-NFκB IN GLIOMA

The NFIA transcription factor is a glioma tumor promoter. The mechanism by which NFIA regulates glioma cell survival and drug resistance is unknown. Here we report that the NFIA pro-survival effect is mediated via an NFIA-NFκB p65 feedforward loop. We examined effects of gain- and loss-of-function manipulations of NFIA and NFκB p65 on cell growth, apoptosis and sensitivity to chemotherapy in patient-derived GBM cells. NFIA inhibited apoptosis by activation of NFkB p65 and its downstream anti-apoptotic factors. Induction of NFκB by NFIA was required for apoptosis evasion, and inhibition of NFκB effectively reversed the NFIA anti-apoptotic effect. Conversely, NFIA knockdown decreased expression of NFκB and its downstream anti-apoptotic genes and increased baseline apoptosis. Using transcriptome- and genome-wide approach, we demonstrated that NFIA directly regulated NFκB transcription. In addition, we found that NFκB activated the NFIA transcription and that knockdown of NFIA was sufficient to attenuate the NFκB pro-survival effect, suggesting a reciprocal regulation between NFIA and NFκB in governing GBM cell growth and survival. Supporting this, NFIA and NFκB expression levels were highly correlated in human GBMs and patient-derived GBM cells. Interestingly, we found that NFIA has splice isoforms in human GBM, which significantly promoted growth of GBM cells and malignant transformation of normal astrocytes. Furthermore, NFIA and the two active isoforms potently increased activity of NFκB p65 in GBM cells. These findings suggest that GBM-active NFIA isoforms differentially affect GBM initiation and progression in part by activating NFκB p65. Collectively, these data define a novel NFIA-NFκB feedforward regulation that promotes GBM tumorigenesis and malignant behavior.

Tumor treating fields inhibit glioblastoma cell migration, invasion and angiogenesis.

Treatment with alternating electric fields at an intermediate frequency (100–300 kHz), referred to as tumor treating fields (TTF) therapy, inhibits cancer cell proliferation. In the present study, we demonstrated that TTF application suppressed the metastatic potential of U87 and U373 glioblastoma cell lines via the NF-kB, MAPK and PI3K/AKT signaling pathways. Wound-healing and transwell assays showed that TTF suppressed cell migration and invasion compared with controls. Soft agar and three-dimensional culture assays showed that TTF inhibited both anchorage-dependent (cell proliferation) and anchorage-independent (colony formation) GBM cell growth. TTF dysregulated epithelial-to-mesenchymal transition-related genes, such as vimentin and E-cadherin, which partially accounted for TTF inhibition of cell migration and invasion. We further demonstrated that TTF application suppressed angiogenesis by downregulating VEGF, HIF1α and matrix metalloproteinases 2 and 9. TTF also inhibited NF-kB transcriptional activity. Collectively, our findings show that TTF represents a promising novel anti-invasion and anti-angiogenesis therapeutic strategy for use in GBM patients.

Abstract 235: SNORD76, a box C/D snoRNA, acts as a tumor suppressor in glioblastoma

Abstract Background Gliomblastoma (GBM) is associated with disproportionately high morbidity and mortality, reflecting the need to develop new diagnostic and therapeutic targets for this disease. Recently, accumulating evidence has suggested that small nucleolar RNAs (snoRNAs) are gaining prominence and are more actively involved in tumorigenesis than previously thought. However, no report concerning the implication of snoRNAs in glioma has been published to date. Methods The expression of SNORD76 and its host gene, GAS5, in glioma patients were evaluated by quantitative PCR. Flow cytometry was used to analyze to cell cycle distribution after SNORD76 over-expression. After SNORD76 over-expression in GBM cell lines, cell growth and anti-tumor effect were investigated in vitro and in vivo. Results SNORD76 expression was selectively decreased in glioblastoma (WHO grade IV) compared with low grades glioma (WHO grade II and III). Forcibly expressed SNORD76 inhibited proliferation and anchorage-independent growth of glioma cells. Flow cytometry demonstrated that enforced SNORD76 expression arrested the cells at S phase of the cell cycle. Western blot Cell cycle-associated proteins cyclin A1, cyclin B1 and p107 were down-regulated after SNORD76 over-expression, while the expression of Rb and pRb increased. The growth of orthotopic tumors was significantly inhibited by forced expression of SNORD76. Conclusion In summary, engineered restoration of SNORD76 caused marked repression of glioma growth in vitro and in vivo. The tumor suppression could be achieved at least partially through inducing S phase arrest in an Rb-associated manner. Thus, SNORD76 may act as a potential tumor suppressive gene in the development and progression of glioblastoma and may be a potential specific glioblastoma biomarker. Citation Format: Luyue chen, Lei Han, kailiang zhang, jianwei wei, peiyu pu, jianning zhang, chunsheng kang. SNORD76, a box C/D snoRNA, acts as a tumor suppressor in glioblastoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 235. doi:10.1158/1538-7445.AM2015-235

Radioactive (125)I seeds inhibit cell growth and epithelial-mesenchymal transition in human glioblastoma multiforme via a ROS-mediated signaling pathway.

BackgroundGlioblastoma multiforme (GBM) is the most common primary central nervous system neoplasm in adults. Radioactive 125I seed implantation has been widely applied in the treatment of cancers. Moreover, previous clinical trials have confirmed that 125I seeds treatment was an effective therapy in GBM. We sought to investigate the effect of 125I seed on GBM cell growth and Epithelial-mesenchymal transition (EMT).MethodsCells were exposed to irradiation at different doses. Colony-formation assay, EdU assay, cell cycle analysis, and TUNEL assay were preformed to investigate the radiation sensitivity. The effects of 125I seeds irradiation on EMT were measured by transwell, Boyden and wound-healing assays. The levels of reactive oxygen species (ROS) were measured by DCF-DA assay. Moreover, the radiation sensitivity and EMT were investigated with or without pretreatment with glutathione. Additionally, nude mice with tumors were measured after treated with radiation.ResultsRadioactive 125I seeds are more effective than X-ray irradiation in inhibiting GBM cell growth. Moreover, EMT was effectively inhibited by 125I seed irradiation. A mechanism study indicated that GBM cell growth and EMT inhibition were induced by 125I seeds with the involvement of a ROS-mediated signaling pathway.ConclusionsRadioactive 125I seeds exhibit novel anticancer activity via a ROS-mediated signaling pathway. These findings have clinical implications for the treatment of patients with GBM by 125I seeds.

Abstract 1584: Targeting the mitotic checkpoint with inhibition of MPS1 kinase enhances radiosensitivity of glioblastoma cancer cells.

Abstract During the cell cycle, genomic stability requires accurate chromosome segregation. Errors in this process can cause aneuploidy and lead to tumorigenesis. To ensure faithful chromosome segregation, cells develop a mechanism called the spindle assembly checkpoint (SAC). Cancer cells are addicted to the components of SAC machinery for a faithful entry of the cell into anaphase. Thus, targeting the molecular mechanisms required for the growth of aneuploid cells may be a more cancer cell specific therapeutic approach applicable to broader tumor histologies. Previously, using a siRNA based RNAi screen we identified MPS1 kinase, (also known as TTK) as an important kinase for GBM cell survival. MPS1 is an essential SAC enzyme aberrantly overexpressed in a wide range of tumors and necessary for tumor cell proliferation. We observed inhibition of GBM cell growth when MPS1 was downregulated by number of MPS1 specific siRNAs. This was further validated using a selective and orally bioavailable MPS1 inhibitor NMS-P715 in various in-vitro cell assays. The inhibition of cell death was induced partly by apoptosis; however, the major mechanism was mitotic catastrophe. Cells treated with NMS-P715 showed an increase in cells in G2-M phase of cell cycle compared to control cells followed by mitotic catastrophe. Moreover, inhibition of MPS1 resulted in radiosensitization of GBM cells. We observed decrease in DNA damage repair and significant retention of γH2AX foci after combination of radiation (RT) with NMS-P715 compared to individual treatments. Next, radiation in combination with NMS-P715 inhibited cell survival ability of GBM cells in a colony formation assay. Further, NMS-P715 could inhibit GBM tumor growth in an orthotopic brain tumor model. Finally, in order to determine MPS1 associated molecular pathways, we compared gene expression profile in MPS1 knockdown cells compared to the control by microarray analysis. Ingenuity pathway and Gene Set Enrichment Analysis were used to investigate the biological relevance of the MPS1 modulated genes. We identified genes important in cell assembly, cell organization, DNA repair and cell death pathways. Thus, inhibiting MPS1 kinase in combination with radiation could represent a promising new approach to GBM therapy. Citation Format: Anita T. Tandle, Ryan Hanson, Uday B. Maachani, Tamalee Meushaw, Shuping Zhao, Uma Shankavaram, Philip Tofilon, Natasha J. Caplen, Kevin Camphausen. Targeting the mitotic checkpoint with inhibition of MPS1 kinase enhances radiosensitivity of glioblastoma cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1584. doi:10.1158/1538-7445.AM2013-1584

Abstract 1983: Thymoquinone induces cell killing in glioblastoma cells through generation of DNA damage and cell cycle arrest

Abstract Glioblastoma (GBM) is the most aggressive and common type of brain tumor in humans. Surgical resection followed by radiation and chemotherapy is the current standard treatment; however, due to the upregulation of several survival pathways, tumor recurrence is quite common with a median survival of 12 to 15 months. Therefore, there is an urgent need for more effective therapeutic strategies for the treatment of glioblastoma. Naturally occurring phytochemicals have steadily received much scientific attention, owing to the fact that many of these compounds have potent action against tumors. Thymoquinone (TQ) is the bioactive compound of the volatile oil extracted from the black seed, Nigella sativa. TQ has shown anti-oxidant, anti-inflammatory and anti-neoplastic actions with a selective cytotoxicity for human cancer cells compared to several normal cells. Here, we show that TQ is able to dose-dependently inhibit colony formation in three distinct glioblastoma cell lines (T98, U87 and Gli36), with the highly tumorigenic Gli36 being the most sensitive to the anti-proliferative effects of TQ. We also show that TQ induces persistent γ-H2AX activation, a marker of DNA double strand breaks, in a time- and dose-dependent manner. TQ also causes G2/M cell cycle arrest in GBM cells to a degree that correlates with the cells’ relative clonogenic sensitivity. Moreover, co-treatment with TQ and N-acetyl cysteine, a simple thiol nucleophile and antioxidant, prevented cell death, DNA double strand breaks, and cell cycle arrest. Taken together, our findings demonstrate that TQ is a potent inhibitor of GBM cell proliferation and growth, and that this effect may be mediated by generation of reactive oxygen species. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1983. doi:1538-7445.AM2012-1983

Abstract 1938: Angiotensin-(1-7), a peptide hormone with therapeutic potential for the treatment of glioblastomas

Abstract Glioblastoma multiforme (GBM), the most common primary malignant brain tumor in adults, is characterized by aggressive proliferation throughout the brain parenchyma and enhanced angiogenesis. Despite multimodality treatment, GBM therapy is only palliative with a median patient survival of less than 10 to 12 months after diagnosis, indicating a need for novel agents with therapeutic potential. Angiotensin-(1-7) [Ang-(1-7)] is an endogenous, seven amino acid peptide hormone with anti-proliferative and anti-angiogenic properties which provides targeted therapy by activating mas, a unique G protein-coupled receptor. In this study, Ang-(1-7) effectively reduced the growth of human GBM in an orthotopic mouse model. Athymic mice with brain tumors resulting from injection of human G48a GBM cells, isolated from a grade 4 astrocytoma, were treated for 28 days with 24 μg/kg/h Ang-(1-7), delivered by osmotic mini-pump. The G48 GBM cells formed an aggressive and invasive phenotype, with outgrowths extending into the brain parenchyma. Ang-(1-7) administration markedly reduced the average tumor burden (a 75% reduction in tumor mass) as compared to untreated control mice (9.4 ± 1.6 x1010 vs 2.4 ± 1.3 x1010 p/sec/cm2/sr, p < 0.022). Histological analysis of brain tissue sections from untreated mice showed a significantly higher percent of Ki67 positive immunoreactivity in tumors as compared to tumor tissue from Ang-(1-7)-treated animals, suggesting that the heptapeptide hormone reduces cell proliferation. In support, proliferation of G48a cultured cells which express the mas receptor was reduced approximately 50% following incubation with 100 nM Ang-(1-7) for five days. Ang-(1-7) treatment also resulted in a marked decrease in MAP kinase ERK1/ERK2 phosphorylation with a concomitant 2-fold increase in the MAP kinase phosphatase DUSP1, suggesting that the heptapeptide hormone negatively regulates GBM cell growth in part by attenuating ERK1/ERK2 activation. Intratumoral vessel density in GBMs from mice administered Ang-(1-7) was attenuated more than 50% as compared to tumors from control animals. VEGF mRNA and protein were decreased over time with a maximal reduction at 8 h in G48a cells following treatment with 100 nM Ang-(1-7). Conversely, the soluble VEGF receptor sFlt-1 was significantly increased in cells incubated with the heptapeptide hormone. sFlt-1, produced by alternative mRNA splicing of Flt-1, is secreted into the circulation and serves as an endogenous trap that sequesters VEGF family ligands, making the angiogenic factors unavailable to the cell-bound VEGF receptors and preventing the downstream activation of pro-angiogenic signaling pathways. Taken together, these studies suggest that Ang-(1-7) inhibits the growth of aggressive, invasive GMBs by pleiotrophic mechanisms and may serve as a first-in-class, targeted, anti-proliferative, anti-angiogenic chemotherapeutic agent for GBM. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1938. doi:1538-7445.AM2012-1938

Abstract 5118: A functional genetic approach in patient-derived glioblastoma stem cells reveals pre-mRNA splicing components to be cancer-lethal gene targets

Abstract Glioblastoma multiforme (GBM) is the most aggressive and common form of brain cancer in adults and is among the deadliest cancers with a median survival period of 12-14 months. This poor prognosis despite aggressive therapy underscores the need for novel therapeutic targets specifically required by GBM cells. Many GBM are thought to arise from a neural stem cell (NSC) origin and, consistent with this premise, tumor-initiating GBM stem cells (GSCs) isolated from patients retain the NSC-like phenotype and molecular profile of primary tumors. Importantly, unlike serum-cultured cell lines, GSCs retain the developmental potential and specific genetic mutations acquired as each patient's tumor progressed from its cell of origin. We hypothesized that these genetic alterations driving GBM growth might also give rise to unique molecular vulnerabilities within the cancer cells. To identify such novel gene targets required for GBM cell growth, but which are dispensable to normal cells, we performed genome-scale RNAi screens in multiple patient-derived GSC isolates and simultaneously counter-screened against primary untransformed human NSCs. From these results, we identified and validated the existence of GBM-lethal genes that, when inhibited, render patient GSCs sensitive to cellular stresses arising within these transformed cells. From these targets, we show that GSCs have an increased requirement for the expression and function of multiple specific members of the pre-mRNA splicing machinery. Notably, loss of specific key splicing proteins resulted in cell cycle arrest and subsequent cell death only in GSCs, identifying the spliceosome as a specific molecular vulnerability in GBM. New treatment strategies for this disease are urgently needed. The identification of spliceosomal proteins as essential for the growth and maintenance of GSCs both adds to our understanding of glioblastoma biology and suggests novel targets for therapeutic intervention. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5118. doi:1538-7445.AM2012-5118

Abstract C169: Inhibition of SREBPs by fatostatin reduces glioblastoma cell proliferation and viability.

Abstract Glioblastoma (GBM) is the most common type of malignant brain tumor. Due to its aggressive invasion of the surrounding tissue, it is one of the most deadly cancers, with an average patient survival rate of 12–18 months after diagnosis despite surgery, radiation and chemotherapy, underscoring the urgent need to find new molecular targets and effective drugs. Recently, The Cancer Genome Atlas identified that the RTK/PI3K/Akt pathway, which can be initiated by epidermal growth factor receptor (EGFR), is activated in about 88% of GBM; this pathway has been recognized as a major driver in promoting malignant cancer cell growth in several cancers. In accordance with this, our group has demonstrated that aberrant EGFR/PI3K/Akt signaling promotes GBM cell growth through sterol regulatory element-binding protein 1 (SREBP-1) mediated fatty acid synthesis and cholesterol uptake, and identified SREBP-1 as a potential molecular target. The focus of our research is to evaluate inhibitors of lipid synthesis/uptake, and to assess their affect on GBM growth. Previously, the small molecular inhibitor fatostatin was shown to effectively inhibit cleavage and activation of SREBPs, suggesting that it can prevent EGFR induced lipid synthesis and uptake and reduce cancer cell viability. Indeed, GBM cells treated with fatostatin exhibited diminished cell proliferation and increased cell death in a dose-dependant manner. These data suggest that alteration of lipid and cholesterol homeostasis through pharmacological inhibitors can suppress glioblastoma growth, providing a new avenue for treating GBM. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C169.

The Novel Hsp90 Inhibitor NXD30001 Induces Tumor Regression in a Genetically Engineered Mouse Model of Glioblastoma Multiforme

Glioblastoma multiforme (GBM) has an abysmal prognosis. We now know that the epidermal growth factor receptor (EGFR) signaling pathway and the loss of function of the tumor suppressor genes p16Ink4a/p19ARF and PTEN play a crucial role in GBM pathogenesis: initiating the early stages of tumor development, sustaining tumor growth, promoting infiltration, and mediating resistance to therapy. We have recently shown that this genetic combination is sufficient to promote the development of GBM in adult mice. Therapeutic agents raised against single targets of the EGFR signaling pathway have proven rather inefficient in GBM therapy, showing the need for combinatorial therapeutic approaches. An effective strategy for concurrent disruption of multiple signaling pathways is via the inhibition of the molecular chaperone heat shock protein 90 (Hsp90). Hsp90 inhibition leads to the degradation of so-called client proteins, many of which are key effectors of GBM pathogenesis. NXD30001 is a novel second generation Hsp90 inhibitor that shows improved pharmacokinetic parameters. Here we show that NXD30001 is a potent inhibitor of GBM cell growth in vitro consistent with its capacity to inhibit several key targets and regulators of GBM biology. We also show the efficacy of NXD30001 in vivo in an EGFR-driven genetically engineered mouse model of GBM. Our findings establish that the Hsp90 inhibitor NXD30001 is a therapeutically multivalent molecule, whose actions strike GBM at the core of its drivers of tumorigenesis and represent a compelling rationale for its use in GBM treatment.

Abstract 777: Rosehip (Rosa canina) extracts prevent Akt-mediated cell proliferation in glioblastoma cells

Abstract Glioblastoma multiforme (GBM) are aggressive malignant tumors that develop in the brain. GBMs demonstrate increased rates of cell proliferation, a lack of apoptosis as well the propensity to migrate to distal sites in the brain. The clinical management of glioblastoma consists of surgical resection followed by radiotherapy and chemotherapy. However, this treatment regimen is not very effective and more effective therapies need to be developed. Activation of several signaling pathways has been associated with the increased proliferative capacity of GBM cells. Activity of the Akt/mTOR pathway is exceptionally high in GBMs and may regulate sensitivity to chemotherapy and radiotherapy. Akt and its downstream effector p70S6 kinase (p70S6K) demonstrate a high amount of activity in GBMs. Inactivation of Akt and p70S6K attenuate GBM cell growth and may inhibit GBM cell proliferation. Therefore, we investigated the antiproliferative capacity of extracts from the Rosehip (Rosa canina) plant. Rosehip extracts have been used as dietary supplements to relieve symptoms associated with diarrhea, gastritis and rheumatoid arthritis. U-1242MG, a human GBM cell line, treated with Rosehip extracts (250 µg/ml) demonstrated a decrease in cell proliferation. The Rosehip extract-mediated decrease in cell proliferation was equal to the decrease of cell proliferation observed when LY294002 (20 µM),a known Akt inhibitor was utilized. Additionally, pretreatment of the U-1242 MG cells with these Rosehip extracts (250 µg/ml) decreased p70S6K phosphorylation, suggesting these extracts prevent GBM cell proliferation by blocking Akt/mTOR signaling mechanisms. Taken together these data suggest that p70S6K positively regulates GBM cell proliferation, and Rosehip extracts may serve as an alternative or supplement to current therapeutic regimens for GBMs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 777.

Phosphotyrosine signaling analysis of site-specific mutations on EGFRvIII identifies determinants governing glioblastoma cell growth

To evaluate the role of individual EGFR phosphorylation sites in activating components of the cellular signaling network we have performed a mass spectrometry-based analysis of the phosphotyrosine network downstream of site-specific EGFRvIII mutants, enabling quantification of network-level effects of site-specific point mutations. Mutation at Y845, Y1068 or Y1148 resulted in diminished receptor phosphorylation, while mutation at Y1173 led to increased phosphorylation on multiple EGFRvIII residues. Altered phosphorylation at the receptor was recapitulated in downstream signaling network activation levels, with Y1173F mutation leading to increased phosphorylation throughout the network. Computational modeling of GBM cell growth as a function of network phosphorylation levels highlights the Erk pathway as crucial for regulating EGFRvIII-driven U87MG GBM cell behavior, with the unexpected finding that Erk1/2 is negatively correlated to GBM cell growth. Genetic manipulation of this pathway supports the model, demonstrating that EGFRvIII-expressing U87MG GBM cells are sensitive to Erk activation levels. Additionally, we developed a model describing glioblastoma cell growth based on a reduced set of phosphoproteins, which represent potential candidates for future development as therapeutic targets for EGFRvIII-positive glioblastoma patients.

Isoquercitrin isolated from Hyptis fasciculata reduces glioblastoma cell proliferation and changes β-catenin cellular localization

Isoquercitrin isolated from the aerial parts of Hyptis fasciculata was evaluated according to its capacity to interfere with glioblastoma (Gbm) cell growth. Gbm cells were incubated with isoquercitrin, quercetin, or rutin at concentrations of 25, 50, and 100 mumol/l for 24, 48, and 72 h. Quercetin and rutin affected Gbm cell proliferation after treatment times of longer than 24 h. However, increasing concentrations of isoquercitrin inhibited 50% of Gbm cell proliferation at 24 h and further reached nearly 90% inhibition at 72 h. This effect did not affect cell morphology, cell viability, or cleaved capase-3 levels, indicating that isoquercitrin did not induce Gbm cell death. A marked reduction in cyclin D1 levels and an increase in p27 levels were observed when 100 micromol/l of isoquercitrin was added to Gbm cells. Interestingly, nuclear beta-catenin staining observed in a subpopulation of untreated Gbm cells was found in the cytoplasm after 100-micromol/l isoquercitrin treatment. Collectively, these data show that isoquercitrin reduces Gbm cell growth without inducing apoptosis, possibly by modulating the control of the cell cycle. Our data also suggest that beta-catenin-mediated signaling may be involved on the antiproliferative activity of isoquercitrin.

MIR-451 and Imatinib mesylate inhibit tumor growth of Glioblastoma stem cells

We examined the microRNA profiles of Glioblastoma stem (CD133+) and non-stem (CD133−) cell populations and found up-regulation of several miRs in the CD133− cells, including miR-451, miR-486, and miR-425, some of which may be involved in regulation of brain differentiation. Transfection of GBM cells with the above miRs inhibited neurosphere formation and transfection with the mature miR-451 dispersed neurospheres, and inhibited GBM cell growth. Furthermore, transfection of miR-451 combined with Imatinib mesylate treatment had a cooperative effect in dispersal of GBM neurospheres. In addition, we identified a target site for SMAD in the promoter region of miR-451 and showed that SMAD3 and 4 activate such a promoter-luciferase construct. Transfection of SMAD in GBM cells inhibited their growth, suggesting that SMAD may drive GBM stem cells to differentiate to CD133− cells through up-regulation of miR-451 and reduces their tumorigenicity. Identification of additional miRs and target genes that regulate GBM stem cells may provide new potential drugs for therapy.

Studies on anthracenes. 3. Synthesis, lipid peroxidation and cytotoxic evaluation of 10-substituted 1,5-dichloro-9(10H)-anthracenone derivatives.

The synthesis of a series of 1,5-dichloro-9(10H)-anthracenones bearing O-linked and N-linked substituents in the 10-position are described. Previous studies have shown that 9-acyloxy 1,5-dichloroanthracenes and 9-acyloxy 1,8-dichloroanthracenes displayed a potential cytotoxic effect. These results have encouraged us in further investigation of potential anthracenone derivatives. Therefore, a series of 10-substituted 1,8-dichloro-9(10H)-anthracenone derivatives were synthesized. These compounds were evaluated for their ability to inhibit the growth of human oral epidermoid carcinoma cells (KB cell line), human cervical carcinoma cells of ME 180 (GBM 8401) and Chinese hamster ovary (CHO) cells, respectively. Compounds 3c and 4c of this series compare favorably in the KB cellular assay with mitoxantrone. Compound 4c showed combined inhibitory action against KB, GBM and CHO cell growth, respectively. In addition, redox property of the compounds for the inhibition of lipid peroxidation in model membranes was determined. Compounds 4b and 4d exhibited stronger antioxidant activity than ascorbic acid, (+)-alpha-tocopherol and mitoxantrone, respectively.