Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The product of the MYC oncogene is widely deregulated in cancer and functions as a regulator of gene transcription. Despite an extensive profile of regulated genes, the transcriptional targets of c-Myc essential for transformation remain unclear. In this study, we show that c-Myc significantly induces the expression of the H19 noncoding RNA in diverse cell types, including breast epithelial, glioblastoma, and fibroblast cells. c-Myc binds to evolutionarily conserved E-boxes near the imprinting control region to facilitate histone acetylation and transcriptional initiation of the H19 promoter. In addition, c-Myc down-regulates the expression of insulin-like growth factor 2 (IGF2), the reciprocally imprinted gene at the H19/IGF2 locus. We show that c-Myc regulates these two genes independently and does not affect H19 imprinting. Indeed, allele-specific chromatin immunoprecipitation and expression analyses indicate that c-Myc binds and drives the expression of only the maternal H19 allele. The role of H19 in transformation is addressed using a knockdown approach and shows that down-regulation of H19 significantly decreases breast and lung cancer cell clonogenicity and anchorage-independent growth. In addition, c-Myc and H19 expression shows strong association in primary breast and lung carcinomas. This work indicates that c-Myc induction of the H19 gene product holds an important role in transformation.
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PMID:The c-Myc oncogene directly induces the H19 noncoding RNA by allele-specific binding to potentiate tumorigenesis. 1670 59

High-grade malignant gliomas (HGG) are the most common and malignant primary central nervous system tumors. Despite therapeutic efforts and advances in biologic knowledge, these diseases remain lethal. Standard treatment of HGG is based on surgery and radiotherapy, usually followed by adjuvant chemotherapy. Many randomized trials addressing the role of post-radiation or "adjuvant" chemotherapy have been conducted in the last three decades, yielding inconclusive results. However, a statistically significant survival benefit with adjuvant chemotherapy has been demonstrated in two meta-analyses with nitrosourea-based adjuvant chemotherapy and a recent phase III trial has demonstrated a survival advantage for radiotherapy with concomitant and adjuvant temozolomide (TMZ) in patients with newly diagnosed glioblastoma. Since high-grade malignant gliomas can seldom be cured, the primary aim of treatments for recurrent disease is to improve progression-free survival (PFS), and to improve or preserve neurological functions. TMZ showed activity even in the treatment of recurrent HGG with a good toxicity profile, whether few data are available for effective treatments in patients treated with adjuvant TMZ. As a result, new agents and novel approaches are required. Furthermore, molecular studies to evaluate chemosensitivity predictors are necessary for patients' selection. Brain metastases are estimated to occur in 20% to 40% of cancer patients, with a higher risk in lung cancer, breast cancer and melanoma. The incidence of brain metastases is rising as results of better imaging procedures and improvements in treatments which leave more cancer patients at risk as survival increases. The prognosis is dependent on a number of factors such as histology of primary tumor, performance status, localization number and size of brain metastases and status of extra cranial disease. Surgery and radiotherapy are indicated in controlled disease with isolated brain metastases. Systemic chemotherapy represents he optimal treatment in chemosensitive tumors with multiple or isolated brain metastases.
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PMID:Primary and metastatic brain tumors. 1687 85

This feature is based on actual questions and answers received and responded to by the Hospice Foundation of America (HFA). This is a service provided for families and support group members of patients with advanced disease by William M. Lamers, MD, HFA Medical Consultant a member of this Journal's Editorial Board. Effective ways to communicate with families and support groups of patients with advanced disease are presented. In this issue, queries and responses are presented addressing symptoms of liver cancer, what type of death to expect from lung cancer, how to help a terminally ill patient just wants to die now, and the clinical course and problems associated with glioblastoma.
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PMID:Symptoms of liver cancer, what is death from lung cancer like? How can I help a patient who just wants to die? 1693 85

The heat shock protein HSP90 serves as a chaperone for receptor protein kinases, steroid receptors, and other intracellular signaling molecules. Targeting HSP90 with ansamycin antibiotics disrupts the normal processing of clients of the HSP90 complex. The platelet-derived growth factor receptor alpha (PDGFRalpha) is a tyrosine kinase receptor up-regulated and activated in several malignancies. Here we show that the PDGFRalpha forms a complex with HSP90 and the co-chaperone cdc37 in ovarian, glioblastoma, and lung cancer cells. Treatment of cancer cell lines expressing the PDGFRalpha with the HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) promotes degradation of the receptor. Likewise, phospho-Akt, a downstream target, is degraded after treatment with 17-AAG. In contrast, PDGFRalpha expression is not affected by 17-AAG in normal human smooth muscle cells or 3T3 fibroblasts. PDGFRalpha degradation by 17-AAG is inhibited by the proteasome inhibitor MG132. High molecular weight, ubiquitinated forms of the receptor are detected in cells treated with 17-AAG and MG132. Degradation of the receptor is also inhibited by a specific neutralizing antibody to the PDGFRalpha but not by a neutralizing antibody to PDGF or by imatinib mesylate (Gleevec). Ultimately, PDGFRalpha-mediated cell proliferation is inhibited by 17-AAG. These results show that 17-AAG promotes PDGFRalpha degradation selectively in transformed cells. Thus, not only mutated tyrosine kinases but also overexpressed receptors in cancer cells can be targeted by 17-AAG.
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PMID:The platelet-derived growth factor receptor alpha is destabilized by geldanamycins in cancer cells. 1707 30

The pyrrole-imidazole alkaloid rac-dibromophakellstatin displayed selective antitumor activity in vitro when tested in 36 cell lines in a cell survival and proliferation assay. The ovarian cancer cell line OVXF 899L proved to be most sensitive (0.60 microM, IC50), followed by the glioblastoma cell line CNXF 498NL (0.93 microM), the non-small lung cancer cell line LXF 529L (0.96 microM), and the uterus cancer cell line UXF 1138L (1.21 microM). The selectivity profile of rac-dibromophakellstatin may be indicative for a novel mechanism of action. Separation of the enantiomers on a chiral HPLC column revealed that only the naturally occurring (-)-dibromophakellstatin is antitumor active. Debromination of the pyrrole moiety leads to complete loss of activity.
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PMID:Antitumor activity of the marine natural product dibromophakellstatin in vitro. 1709 16

Colorectal cancer (CRC) is a major cause of cancer morbidity and mortality, and elucidation of its underlying genetics has advanced diagnostic screening, early detection, and treatment. Because CRC genomes are characterized by numerous non-random chromosomal structural alterations, we sought to delimit regions of recurrent amplifications and deletions in a collection of 42 primary specimens and 37 tumor cell lines derived from chromosomal instability neoplasia and microsatellite instability neoplasia CRC subtypes and to compare the pattern of genomic aberrations in CRC with those in other cancers. Application of oligomer-based array-comparative genome hybridization and custom analytic tools identified 50 minimal common regions (MCRs) of copy number alterations, 28 amplifications, and 22 deletions. Fifteen were highly recurrent and focal (<12 genes) MCRs, five of them harboring known CRC genes including EGFR and MYC with the remaining 10 containing a total of 65 resident genes with established links to cancer. Furthermore, comparisons of these delimited genomic profiles revealed that 22 of the 50 CRC MCRs are also present in lung cancer, glioblastoma, and/or multiple myeloma. Among 22 shared MCRs, nine do not contain genes previously shown genetically altered in cancer, whereas the remaining 13 harbor 35 known cancer genes, of which only 14 have been linked to CRC pathogenesis. Together, these observations point to the existence of many yet-to-be discovered cancer genes driving CRC development, as well as other human cancers, and show the utility of high-resolution copy number analysis in the identification of genetic events common and specific to the development of various tumor types.
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PMID:Common and distinct genomic events in sporadic colorectal cancer and diverse cancer types. 1800 16

Aberrant expression levels of epidermal growth factor receptor (EGFR) and its cognate ligands have been recognized as one of the causes of cancer progression. To investigate the validity of EGFR ligands as targets for cancer therapy, we examined the expression of EGFR ligands and in vitro anti-tumor effects of small interference RNA (siRNA) for EGFR ligands in various cancer cells. HB-EGF expression was dominantly elevated in ovarian, gastric, and breast cancer, melanoma and glioblastoma cells, whereas amphiregulin was primarily expressed in pancreatic, colon, and prostate cancer, renal cell carcinoma and cholangiocarcinoma cells. Transfection of siRNAs for HB-EGF or amphiregulin into these cells significantly increased the numbers of apoptotic cells with attenuation of EGFR and ERK activation. In lung cancer cells, any EGFR ligand was not recognized as a validated target for cancer therapy. These results suggest that HB-EGF and amphiregulin are promising targets for cancer therapy.
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PMID:Validation of HB-EGF and amphiregulin as targets for human cancer therapy. 1802 15

One of the specific forms of progression of malignant tumors of the central nervous system is meningeal dissemination. Meningeal dissemination is a condition in which tumor cells migrate to the brain surface and sub arachnoid space via cerebrospinal fluid and then infiltrate there. This condition can arise from both primary and metastatic brain tumors, with reported incidences of 4.2% for primary tumors and 5.1% for metastatic tumors. Meningeal dissemination frequently arises from germinoma, medulloblastoma, ependymoma and glioblastoma in cases of primary brain tumors and frequently arises from breast cancer, lung cancer and gastric cancer in cases of metastatic brain tumors, known as meningeal carcinomatosis. The prognosis of meningeal dissemination is poor, and conventional treatments such as systemic chemotherapy and radiation therapy are ineffective. Intrathecal infusion of anti neoplastic agents is one of the options for treatment of meningeal dissemination. The advantage of intrathecal chemotherapy is that the anti neoplastic agent is rapidly diffused in the sub arachnoid space, and its duration of activity is long due to its slow clearance and metabolism. Routes of administration include infusion into the lateral ventricle by puncture of the Ommaya reservoir, infusion into the sub arachnoid space by lumbar puncture, or both of these procedures performed alternately or simultaneously, and methods of infusion include bolus injection and ventriculo lumbar perfusion. Commonly used drugs include methotrexate (MTX), cytarabine (Ara-C), and 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)- 1-nitrosourea hydrochloride (ACNU), and some new drugs have also begun to be used clinically. Although there are differences depending on the histological type of the tumor, the anti neoplastic agent administered and the method of administration, the response rate is about 40-80% and mean survival time is about 4-25 months. Although side effects of the anti neoplastic agents are not as severe as with agents used for systemic chemotherapy, specific side effects include nonspecific drug-induced meningitis or ventriculitis, transient or permanent paralysis and leukoencephalopathy. These side effects can be alleviated by reducing the dose or discontinuing the anti neoplastic agents, and a small dose of an adrenocorticosteroid is sometimes administered simultaneously. Bacterial meningitis is another complication and requires discontinuation of anti neoplastic agents, removal of the Ommaya reservoir, or systemic or intrathecal administration of antibiotic agents. Although meningeal dissemination is a rare metastatic condition with a poor prognosis, there have been some reports of successful treatment using this method, which is expected to be widely used in the future.
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PMID:[Intrathecal infusion of the antineoplastic agents for meningeal dissemination]. 1863 17

Gefitinib and erlotinib are both selective EGFR tyrosine kinase inhibitors (EGFR-TKIs) that have produced responses in a small subgroup of lung cancer patients. The strongest evidence for a role of EGFR in the biology of glioblastoma stems from clinical trials in which 15-20% of recurrent glioblastoma patients experienced significant tumour regression in response to these small-molecule EGFR kinase inhibitors. We examined the protein-kinase domain of the EGFR gene, EGFR protein expression and EGFR gene amplification in 20 cases of recurrent GBMs. EGFR protein over-expression was found in 65% of cases. EGFR protein over-expression was associated with EGFR gene amplification in 35% of cases, and with high polysomy in 15% of cases. No mutations were found in the TK domain of the EGFR gene. Our results confirm that mutations in the kinase domain are absent in recurrent GBM, and this might be a preponderant factor in the lack of major clinical responses of TKIs in GBM, recent studies have suggested that responsiveness to EGFR kinase inhibitors was strongly associated with coexpression of EGFRvIII and PTEN. Further prospective validation of EGFRvIII and PTEN as predictors of the clinical response to EGFR kinase inhibitors in recurrent GBM is strongly anticipated.
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PMID:Analysis of EGFR gene amplification, protein over-expression and tyrosine kinase domain mutation in recurrent glioblastoma. 1875 56

The aim of this study was to determine the efficacy of sagopilone (ZK-EPO), a novel epothilone, compared with other anticancer agents in orthotopic models of human primary and secondary brain tumors. Autoradiography and pharmacokinetic analyses were performed on rats and mice to determine passage across the blood-brain barrier and organ distribution of sagopilone. Mice bearing intracerebral human tumors (U373 or U87 glioblastoma, MDA-MB-435 melanoma, or patient-derived non-small-cell lung cancer [NSCLC]) were treated with sagopilone 5-10 mg/kg, paclitaxel 8-12.5 mg/kg (or temozolomide, 100 mg/kg) or control (vehicle only). Tumor volume was measured to assess antitumor activity. Sagopilone crossed the blood-brain barrier in both rat and mouse models, leading to therapeutically relevant concentrations in the brain with a long half-life. Sagopilone exhibited significant antitumor activity in both the U373 and U87 models of human glioblastoma, while paclitaxel showed a limited effect in the U373 model. Sagopilone significantly inhibited the growth of tumors from CNS metastasis models (MDA-MB-435 melanoma and patient-derived Lu7187 and Lu7466 NSCLC) implanted in the brains of nude mice, in contrast to paclitaxel or temozolomide. Sagopilone has free access to the brain. Sagopilone demonstrated significant antitumor activity in orthotopic models of both glioblastoma and CNS metastases compared with paclitaxel or temozolomide, underlining the value of further research evaluating sagopilone in the treatment of brain tumors. Sagopilone is currently being investigated in a broad phase II clinical trial program, including patients with glioblastoma, NSCLC, breast cancer, and melanoma.
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PMID:Sagopilone crosses the blood-brain barrier in vivo to inhibit brain tumor growth and metastases. 1878 Aug 14


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