Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cancer stem cells (CSCs) are a minute sub-population of self-renewing, immortal cells, which can be responsible for chemoresistance observed in the treatment of cancer. CSCs are similar to cancer cells requiring telomerase activity or alternative mechanisms for their proliferation and regeneration. This study explored the correlation between CD133 (stem cell marker) and telomerase expression using CD133+ cells isolated from the glioma GOS-3 cell line with magnetic affinity cell sorting (MACS). GOS-3 CD133+ showed a transcription downregulation of hTERT ( approximately 100-fold decrease) compared with CD133- cells. In order to further substantiate the novel finding, serum deprivation was adopted to enrich CD133 expression in GOS-3 cells. A pronounced upregulation of cd133 and downregulation of telomerase expression were produced as a consequence of decreasing serum supplement levels in GOS-3 cells. These findings showed for the first time that telomerase is downregulated in brain cancer stem cells compared to cancer cells.
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PMID:Telomerase downregulation in cancer brain stem cell. 1943 Aug 94

Malignant gliomas are characterized by a short median survival which is largely impacted by the resistance of these tumors tochemo- and radiotherapy. Recent studies suggest that a small subpopulation of cancer stem cells, which are highly resistant to gamma-radiation, has the capacity to repopulate the tumors and contribute to their malignant progression. gamma-radiation activates the process of autophagy and inhibition of this process increases the radiosensitivity of glioma cells; however, the role of autophagy in the resistance of glioma stem cells (GSCs) to radiation has not been yet reported. In this study we examined the induction of autophagy by gamma-radiation in CD133+ GSCs. Irradiation of CD133+ cells induced autophagy within 24-48 hr and slightly decreased the viability of the cells. gamma-radiation induced a larger degree of autophagy in the CD133+ cells as compared with CD133- cells and the CD133+ cells expressed higher levels of the autophagy-related proteins LC3, ATG5 and ATG12. The autophagy inhibitor bafilomycin A1 and silencing of ATG5 and beclin1 sensitized the CD133+ cells to gamma-radiation and significantly decreased the viability of the irradiated cells and their ability to form neurospheres. Collectively, these results indicate that the induction of autophagy contributes to the radioresistance of these cells and autophagy inhibitors may be employed to increase the sensitivity of CD133+ GSCs to gamma-radiation.
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PMID:The induction of autophagy by gamma-radiation contributes to the radioresistance of glioma stem cells. 1943 Nov 42

Oncolytic herpes simplex viruses (HSV) hold promise for therapy of glioblastoma multiforme (GBM) resistant to traditional therapies. We examined the ability of genetically engineered HSV to infect and kill cells that express CD133, a putative marker of glioma progenitor cells (GPC), to determine if GPC have an inherent therapeutic resistance to HSV. Expression of CD133 and CD111 (nectin-1), the major entry molecule for HSV, was variable in six human glioma xenografts, at initial disaggregation and after tissue culture. Importantly, both CD133+ and CD133- populations of glioma cells expressed CD111 in similar relative proportions in five xenografts, and CD133+ and CD133- glioma cell subpopulations were equally sensitive to killing in vitro by graded dilutions of wild-type HSV-1(F) or several different gamma(1)34.5-deleted viruses. GPC did not display an inherent resistance to HSV. While CD111 expression was an important factor for determining sensitivity of glioma cells to HSV oncolysis, it was not the only factor. Our findings support the notion that HSV will not be able to effectively enter, infect, and kill cells in tumors that have low CD111 expression (<20%). However, virotherapy with HSV may be very effective against CD111+ GPC resistant to traditional therapies.
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PMID:Engineered herpes simplex viruses efficiently infect and kill CD133+ human glioma xenograft cells that express CD111. 1952 65

Primary glial tumors of the central nervous system, most commonly glioblastoma multiforme (GBM), are aggressive lesions with a dismal prognosis. Despite identification and isolation of human brain tumor stem cells (BTSCs), characteristics that distinguish BTSCs from neural stem cells remain to be elucidated. We cultured cells isolated from gliomas, using the neurosphere culture system, to understand their growth requirements. Both CD133(+) and CD133(-) adult GBM BTSCs proliferated in the absence of exogenous mitogenic stimulation and gave rise to multipotent GBM spheres that were capable of self-renewal. Epidermal growth factor (EGF) and fibroblast growth factor-2 enhanced GBM BTSC survival, proliferation, and subsequent sphere size. Blockade of EGF receptor (EGFR) signaling reduced exogenous mitogen-independent GBM sphere growth. Implantation of as few as 10 exogenous mitogen-independent GBM BTSCs led to the formation of highly invasive intracranial tumors, which closely resembled human GBMs, in immunocompromised mice. These results demonstrate that exogenous mitogen independence, mediated in part through EGFR signaling, is one characteristic that distinguishes CD133(+) and CD133(-) GBM BTSCs from neural stem cells. This novel experimental system will permit the elucidation of additional constitutively activated mechanisms that promote GBM BTSC survival, self-renewal, and proliferation.
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PMID:Proliferation of human glioblastoma stem cells occurs independently of exogenous mitogens. 1954 33

Hedgehog pathway activity has been demonstrated in malignant glioma. However, its role in tumor growth has not been determined. Here we demonstrate that pharmacological inhibition of the Hedgehog pathway in established orthotopic malignant glioma xenografts confers a survival advantage. Pathway inhibition is measured in transplanted human tumor cells and not in host mouse brain. Correspondingly, survival benefit is observed only in tumors with an operational Hedgehog pathway. These data indicate that Hedgehog signaling regulates the growth of select malignant gliomas. We also demonstrate that Hedgehog pathway component and gene target expression segregate to CD133(+) tumor initiating cells. Treated mice eventually succumb to disease, thus, targeting the Hedgehog pathway in CD133(+) cells produces significant, but incomplete tumor regression. Therefore, our studies suggest that more complete tumor regression may require the inclusion of other therapeutic targets, including CD133(-) cells.
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PMID:Targeted inhibition of the Hedgehog pathway in established malignant glioma xenografts enhances survival. 1961

Hypoxia contributes to the progression of a variety of cancers by activating adaptive transcriptional programs that promote cell survival, motility and tumor angiogenesis. Although the importance of hypoxia and subsequent hypoxia-inducible factor-1alpha (HIF-1alpha) activation in tumor angiogenesis is well known, their role in the regulation of glioma-derived stem cells is unclear. In this study, we show that hypoxia (1% oxygen) promotes the self-renewal capacity of CD133-positive human glioma-derived cancer stem cells (CSCs). Propagation of the glioma-derived CSCs in a hypoxic environment also led to the expansion of cells bearing CXCR4 (CD184), CD44(low) and A2B5 surface markers. The enhanced self-renewal activity of the CD133-positive CSCs in hypoxia was preceded by upregulation of HIF-1alpha. Knockdown of HIF-1alpha abrogated the hypoxia-mediated CD133-positive CSC expansion. Inhibition of the phosphatidylinositol 3-kinase(PI3K)-Akt or ERK1/2 pathway reduced the hypoxia-driven CD133 expansion, suggesting that these signaling cascades may modulate the hypoxic response. Finally, CSCs propagated at hypoxia robustly retained the undifferentiated phenotype, whereas CSCs cultured at normoxia did not. These results suggest that response to hypoxia by CSCs involves the activation of HIF-1alpha to enhance the self-renewal activity of CD133-positive cells and to inhibit the induction of CSC differentiation. This study illustrates the importance of the tumor microenvironment in determining cellular behavior.
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PMID:Hypoxia promotes expansion of the CD133-positive glioma stem cells through activation of HIF-1alpha. 1971 46

Prominin1 (Prom1, also known as CD133 in human) has been widely used as a marker for cancer stem cells (CSCs), which self-renew and are tumorigenic, in malignant tumors including glioblastoma multiforme (GBM). However, there is other evidence showing that Prom1-negative cancer cells also form tumors in vivo. Thus it remains controversial whether Prom1 is a bona fide marker for CSCs. To verify if Prom1-expressing cells are essential for tumorigenesis, we established a mouse line, whose Prom1-expressing cells can be eliminated conditionally by a Cre-inducible DTA gene on the Prom1 locus together with a tamoxifen-inducible CreER(TM), and generated glioma-initiating cells (GICs-LD) by overexpressing both the SV40 Large T antigen and an oncogenic H-Ras(L61) in neural stem cells of the mouse line. We show here that the tamoxifen-treated GICs-LD (GICs-DTA) form tumor-spheres in culture and transplantable GBM in vivo. Thus, our studies demonstrate that Prom1-expressing cells are dispensable for gliomagenesis in this mouse model.
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PMID:Glioblastoma formation from cell population depleted of Prominin1-expressing cells. 1971 38

The stem cell marker CD133/prominin-1, is a pentaspan membrane glycoprotein, which has also been identified as a cancer stem cell (CSC) marker in several solid tumor types, including those of the prostate, liver, colon and brain. The function of CD133 in these tumors is still unknown. We hypothesize that the function of CD133 is correlated with the characteristics of the CD133+ CSCs and may affect the growth of the tumor cell population as a whole. In this study we used antisense oligodeoxynucleotides (ASODNs) of CD133 to knock-down (KD) CD133 expression. We showed that the CD133-KD inhibited proliferation of U251 human glioma cells, decreased the colony forming ability and altered the cell cycle distribution in Huh-7 human hepatocellular carcinoma cells. Our data suggest that CD133 may play an important functional role in the growth of these tumor cells. Moreover, this study also showed that prominin-2, another protein in the same family as CD133/prominin-1, may not have a similar function.
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PMID:Effect of CD133/prominin-1 antisense oligodeoxynucleotide on in vitro growth characteristics of Huh-7 human hepatocarcinoma cells and U251 human glioma cells. 1972 56

Hedgehog signaling is aberrantly activated in glioma, medulloblastoma, basal cell carcinoma, lung cancer, esophageal cancer, gastric cancer, pancreatic cancer, breast cancer, and other tumors. Hedgehog signals activate GLI family members via Smoothened. RTK signaling potentiates GLI activity through PI3K-AKT-mediated GSK3 inactivation or RAS-STIL1-mediated SUFU inactivation, while GPCR signaling to Gs represses GLI activity through adenylate cyclase-mediated PKA activation. GLI activators bind to GACCACCCA motif to regulate transcription of GLI1, PTCH1, PTCH2, HHIP1, MYCN, CCND1, CCND2, BCL2, CFLAR, FOXF1, FOXL1, PRDM1 (BLIMP1), JAG2, GREM1, and Follistatin. Hedgehog signals are fine-tuned based on positive feedback loop via GLI1 and negative feedback loop via PTCH1, PTCH2, and HHIP1. Excessive positive feedback or collapsed negative feedback of Hedgehog signaling due to epigenetic or genetic alterations leads to carcinogenesis. Hedgehog signals induce cellular proliferation through upregulation of N-Myc, Cyclin D/E, and FOXM1. Hedgehog signals directly upregulate JAG2, indirectly upregulate mesenchymal BMP4 via FOXF1 or FOXL1, and also upregulate WNT2B and WNT5A. Hedgehog signals induce stem cell markers BMI1, LGR5, CD44 and CD133 based on cross-talk with WNT and/or other signals. Hedgehog signals upregulate BCL2 and CFLAR to promote cellular survival, SNAI1 (Snail), SNAI2 (Slug), ZEB1, ZEB2 (SIP1), TWIST2, and FOXC2 to promote epithelial-to-mesenchymal transition, and PTHLH (PTHrP) to promote osteolytic bone metastasis. KAAD-cyclopamine, Mu-SSKYQ-cyclopamine, IPI-269609, SANT1, SANT2, CUR61414 and HhAntag are small-molecule inhibitors targeted to Smoothened, GANT58, GANT61 to GLI1 and GLI2, and Robot-nikinin to SHH. Hedgehog signaling inhibitors should be used in combination with RTK inhibitors, GPCR modulators, and/or irradiation for cancer therapy.
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PMID:Hedgehog target genes: mechanisms of carcinogenesis induced by aberrant hedgehog signaling activation. 1986 Jun 66

Although significant progresses were made in the field of molecular biology of malignant cerebral gliomas, the prognostic of these tumors continues to be reserved. One of the therapeutic failure reasons is the incomplete knowledge regarding the origin of these tumors and cells features, which in fact represent an obstacle in developing a cell and molecular therapy guided against malignant cells responsible for the tumor development and for the therapeutic resistance. Initiation and characterization of glioblastoma cell lines represents an essential step in order to obtain a better in vitro and in vivo experimental model for glioblastoma. We describe here a new glioblastoma line, named T11, which was successfully isolated in our laboratories starting with a tumor sample obtained intraoperative from a 58 years-old female patient. The histopathological evaluation showed a grad IV WHO glioma (glioblastoma). The sample was prepared by manual fragmentation, followed by enzymatic digestions using different concentration of trypsin. The cell line has been cultivated for more than 150 passages. The characterization of the glioblastoma line consisted in the evaluation of cells proliferation capacity (growth curve), morphological features, karyotyping and identification of specific markers. We found that T11 expressed specific markers for glial progenitors and astrocytes (glial fibrillary acidic protein-GFAP); oligodendrocites (A2B5; O4), and microglia (CD45, CD 11b). Cells were negative for neuronal lineage markers like beta3-tubulin and NCAM. In order to evaluate the differentiation grade of T11 cell line, the presence of stem cell markers (nestin, CD133) was explored. T11l cells expressed higher level of nestin and lower level of CD133 comparing with standard glioblastoma cell line U87. T11 cell line expressed VEGF and Bcl-2, but not EGFR and Mdrl and Bax. This new line has distinct and unique characteristics when compared with standard glioblastoma cell line (e.g., U87) and may become a new and useful in vitro model for glioblastoma.
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PMID:Isolation and partial characterization of a new human glioblastoma cell line. 1988 54


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