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)

Cytokines such as interleukin-1 (IL-1) and IL-6 stimulate the hypothalamic-pituitary-adrenal (HPA) axis. In addition, these proteins affect pituitary cell proliferation in vitro. Thymosin fraction 5 (TF5) is a partially purified preparation of the bovine thymus that enhances immune system functioning. Because TF5 similarly stimulates the HPA axis, we examined the effects of this preparation on neuroendocrine tumor cell proliferation. Cells of the PRL-secreting rat anterior pituitary adenoma, MMQ (5-50 x 10(3) cells/well), were exposed to vehicle (RPMI-1640 containing 2.5% FCS, 7.5% horse serum, and antibiotics) or TF5 (100-500 microg/ml) for up to 96 h and the proliferation of MMQ cells monitored using the MTT assay (3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide). TF5-mediated inhibition of cell proliferation was dependent on both TF5 concentration and the initial MMQ cell number. Minimal reductions in optical densities resulted from exposure to 100 microg/ml TF5, whereas the highest concentration of this preparation (i.e. 500 microg/ml) completely blocked MMQ cell division. The concentration-dependent effects of TF5 were particularly striking at initial plating densities of 25 and 50 x 10(3) MMQ cells/well; in contrast, all concentrations of TF5 completely inhibited MMQ cell growth at 5 and 10 x 10(3) cells/well. The antiproliferative actions of TF5 on MMQ cells were demonstrable within 24 h and remained for up to 96 h as determined by the MTT assay and actual cell counts. Because the highest densities of MMQ cells were partially refractive to the antiproliferative effects of TF5, we examined the effects of PRL (1-1000 nM) and MMQ cell conditioned medium (50%) on TF5 inhibition of MMQ adenoma proliferation. The TF5 concentration-dependent inhibition of MMQ cell growth was largely reversed by the 50% conditioned medium, whereas PRL slightly potentiated the antiproliferative actions of TF5. The proliferation of the rat C6 glioma cell line (10-30 x 10(3) cells/well) demonstrated greater sensitivity to TF5: concentrations as low as 10 microg/ml TF5 inhibited C6 cell proliferation (P < 0.01), and near-maximal inhibition was noted at 200 microg/ml TF5. Significant reductions in MMQ and C6 cell viabilities accompanied decreases in cell number and morphological analysis indicated these cells were dying by apoptosis. The peptides thymosin alpha1 (T alpha1), thymosin beta4 (T beta4), MB35, and MB40 had no effect on either MMQ or C6 cell proliferation, indicating that these TF5 components are not the principle active peptides. Therefore, TF5 was further separated into 60 fractions by preparative reverse phase HPLC. HPLC fractions 17, 25, 26, and 27 significantly suppressed MMQ cell proliferation (P < 0.01) to the same extent as TF5; other HPLC fractions had no effect. These data demonstrate a new biological property of TF5: the inhibition of cell proliferation and the induction of apoptosis in neuroendocrine tumor cells. The proliferation effects were time and concentration dependent and could be partially reversed by an activity present in the MMQ cell conditioned medium. Thus, TF5 and cytokines have opposite effects on adenoma cells because IL-2 and IL-6 stimulate GH3 cell proliferation. We propose that circulating thymic peptides may act to prevent pituitary adenoma and glioma tumor formation, an action opposed by autocrine growth factors secreted by these tumors.
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PMID:Thymosin fraction 5 inhibits the proliferation of the rat neuroendocrine MMQ pituitary adenoma and C6 glioma cell lines in vitro. 952 5

Fifty-eight skin biopsies and three primary internal tumors from patients affected by the rare hereditary disease xeroderma pigmentosum (XP) were studied by an improved PCR-single strand conformation polymorphism analysis to detect the mutations of the tumor suppressor gene p53. The results from cutaneous XP tumors, including 27 squamous cell carcinomas and 6 basal cell carcinomas, show a very high level (86%) of p53 mutations. The analysis of mutations found in XP skin cancers according to the complementation group of the patients shows that tandem CC-->TT transitions are a characteristic of XP-C patients with a frequency much higher in their skin tumors (85%) compared with tumors in XP patients who do not belong to group C (33%). In all XP-C biopsies, mutations were due to replication of unrepaired DNA lesions on the nontranscribed strand of the p53 gene, substantiating the preferential repair in vivo of the transcribed strand of this gene in human tissues. For the first time, we were able to analyze three primary internal tumors (a neuroendocrine tumor of the thyroid, a gastric adenocarcinoma, and a glioma of the brain) of young XP children. All of them contained one mutation on the p53 gene, which were different from the ones found in the XP skin tumors and could have resulted from unrepaired lesions caused by oxidative damage.
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PMID:p53 mutations in skin and internal tumors of xeroderma pigmentosum patients belonging to the complementation group C. 976 70