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)

The DNA labile sites induced by two nitrosoureas, nimustine (ACNU) and ramustine (MCNU) synthesised in Japan, have been examined in highly reiterated DNA sequences of rat glioma cells. Reiterated fragments of 167 and 203 base pairs (bp), obtained after Hind III and Hae III restriction endonuclease digestion of rat glioma cells DNA, were used as target DNA sequences to determine the labile sites. In vitro reaction with ACNU and MCNU resulted in scission products corresponding to the locations of guanine. Subsequent piperidine hydrolysis produced more frequent breaks of the phosphodiester bonds at guanine positions, thus forming alkali-labile sites.
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PMID:DNA lability induced by nimustine and ramustine in rat glioma cells. 323 17

In order to analyze the efficacy of combination therapy with Hu-IFN-beta, ACNU and radiation (IAR), nine patients with malignant glioma were treated as a control study. They received 100 X 10(4) IU Hu-IFN-beta daily for seven days intravenously or intratumorally, 3 mg/kg ACNU on day 2 and 5,000-6,000 rads of radiation from day 3. Four out of nine patients showed complete response and one partial response with this IAR therapy. Case 1 was a 64-year-old man who had glioblastoma in the left frontal lobe. Postoperative residual tumors disappeared completely with this therapy. Case 3 was a 8-year-old girl who had an enhanced high-density lesion in the medulla oblongata and pons. After IAR therapy, the high-density lesion was completely vanished and her clinical manifestations of multiple cranial nerve palsy and pyramidal sign were improved remarkably. The major side effects of IAR therapy were mild or moderate myelosuppression, and some patients also showed hepatic dysfunction, mild fever and gastrointestinal toxicities. However, all these side effects were mild and transient and soon recovered to normal levels. These results suggest that IAR therapy is effective and will prolong the survival time of patients with malignant glioma.
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PMID:[Combination therapy with IFN-beta, ACNU and radiation (IAR) in malignant brain tumors]. 345 40

Reserpine was shown to enhance the cytotoxicity of ACNU in both C6 and C6/ACNU rat glioma cells in vitro and also to enhance the chemotherapeutic effect of ACNU in C6/ACNU-bearing rats (C6/ACNU meningeal gliomatosis rats), in which ACNU resistance could be partially overcome by reserpine. When reserpine was added to the culture at a concentration of 10 microM, the IC50 of ACNU for C6/ACNU cells decreased to the level of that for C6 cells. Intracellular uptake of ACNU in C6/ACNU cells increased and the efflux from the cells decreased when 20 microM reserpine was added to the culture. In in vivo experiments, combined ACNU (1 mg/kg) and reserpine (250 micrograms/kg) therapy by intrathecal injection of these drugs improved % ILS (increased life span) with statistical significance compared with that after treatment with ACNU alone. The probable explanation of the enhanced cytotoxic-effect of ACNU in ACNU-resistant glioma cells presented in in vitro and in vivo is increased intracellular ACNU concentration resulting from inhibition of the efflux of ACNU from the resistant cells.
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PMID:[Overcoming of ACNU resistance in a subline of rat glioma in vitro and in vivo by reserpine]. 345 96

Reserpine was found to enhance the cytotoxicity of ACNU on ACNU-resistant C6 glioma (C6/ACNU) cells in vitro. When reserpine was added along with ACNU to the C6/ACNU cells in vitro. When reserpine was added along with ACNU to the C6/ACNU culture in vitro at a concentration of 10 microM, the IC50 of ACNU for C6/ACNU cells decreased to the level of that for C6 cells and ACNU resistance was completely overcome in vitro. Furthermore, intracellular uptake of ACNU increased in both sensitive (C6) and resistant (C6/ACNU) glioma cells when 20 microM reserpine was added to the culture medium. Reserpine (20 microM) enhanced the cellular level of ACNU in C6 cells 1.5-fold and enhanced the level of ACNU in C6/ACNU cells 4-fold. The amount of ACNU incorporated into C6/ACNU cells reached the same level as that incorporated into C6 cells. The enhanced cytotoxicity of ACNU in vitro could be explained by the effective intracellular accumulation of ACNU resulting from the increase of intracellular uptake of ACNU in C6/ACNU cells by reserpine.
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PMID:Enhanced effect of reserpine upon growth-inhibitory action of ACNU on ACNU-resistant C6 glioma. 345 11

Combined effects of ACNU and 5-Fu on rat glioma clone-6 cells grown exponentially as monolayers and in multicell spheroids (500-600 micron in diameter) were analyzed by the colony-forming assay. Cells in spheroids with central necroses were more sensitive to ACNU than cells in monolayer, although a large fraction of the cells in these spheroids was resistant to 5-Fu. The effect of ACNU was enhanced by the combined treatment with 5-Fu for cells in both spheroids and monolayers, and was more remarkable when 5-Fu was administered 24 hr prior to ACNU treatment. The enhancement was mainly due to a decrease in the number of spheroid-cells resistant to 5-Fu. Isobologram analysis indicated that the enhancement was supra-additive when a low concentration of 5-Fu was combined with a high concentration of ACNU. It is suggested that a low dose of 5-Fu combined with a high dose of ACNU may preferentially kill more cells in solid tumors.
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PMID:Combined effect of ACNU and 5-FU on rat glioma cells in spheroids and monolayer cultures. 346 Sep 69

Blood flow of transplanted intracerebral rat gliomas was measured before and after a constant I.V. infusion of angiotensin II-induced arterial hypertension using hydrogen clearance method. The brain tumor model was produced in syngeneic Wistar-King-Aptekman male rats by stereotaxic inoculation of ethylnitrosourea-induced glioma cells (KEG-1). Induced hypertension by angiotensin II infusion resulted in a significant increase in tumor blood flow compared with control levels (P less than 0.001). In addition, the therapeutic effect of administration of 3-[(4-amino-2-methyl-5-pyrimidinyl) ethyl] -1-(2-chloroethyl)-1-nitrosourea (ACNU) during angiotensin II-induced hypertension was evaluated. At 12 days after implantation, tumor-bearing rats were administrated angiotensin II as the mean blood pressure reached 150 mmHg, followed by ACNU injection, maintained the same blood pressure for 20 minutes. ACNU with induced hypertension group showed a median survival time of 27.0 days, which was significantly (P less than 0.02) longer than that of ACNU alone (22.0 days). It is therefore suggested that chemotherapy with angiotensin II-induced hypertension has a enhancing effect on chemotherapy for improving the drug delivery to tumor tissue by a increased tumor blood flow.
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PMID:[Experimental studies on induced hypertension chemotherapy of intracerebral inoculated gliomas in rats]. 346 30

A nitrosourea derivative, ACNU (nimustine hydrochloride), is often used in the chemotherapy of brain tumors and shows considerable efficacy, since it crosses the blood-brain barrier (B.B.B.). This drug is also considered to be useful for intrathecal treatment of meningeal gliomatosis (MG) because of its short half-life in the blood or cerebrospinal fluid (CSF) and its strong cytotoxicity for glioma cells. In order to evaluate the efficacy of intrathecal therapy of MG with ACNU, MG models, which were produced by intracisternal inoculation of rat C6 glioma, were treated with intrathecal or intravenous administration of ACNU. When intrathecally administered 1 day or 3 days after tumor inoculation, ACNU (1 mg/kg) significantly prolonged the survival time of MG rats, where ILS was 35.7 to 42.9% and 24.1 to 25.0%, respectively. In MG rats which were treated intrathecally with ACNU (1 mg/kg) 5 days after tumor inoculation or intravenously with ACNU (15 mg/kg), ACNU failed to prolong survival time compared with the controls. It might therefore be suggested that intrathecal chemotherapy with a low dose of ACNU is effective in the early stages of MG, in which intravenous treatment with a high dose of ACNU is ineffective.
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PMID:[Intrathecal ACNU for the treatment of a meningeal gliomatosis model]. 346 57

Reserpine enhanced in vitro the cytotoxicity of 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) in both the C6 glioma and its ACNU-resistant subline, C6/ACNU. Reserpine also enhanced the chemotherapeutic effect of ACNU in C6/ACNU-bearing (C6/ACNU-meningeal gliomatosis) rats, in which ACNU resistance could be modulated by combined ACNU and reserpine therapy. When 10 microM reserpine was added to ACNU in culture, the concentration of drug required for 50% inhibition of cell growth (IC50) of ACNU for C6/ACNU cells decreased to the level of that for C6 cells. When 20 microM reserpine was added to the culture, intracellular uptake of ACNU in C6/ACNU cells increased further and the efflux of the drug from the cells decreased. In in vivo experiments in rats, combined chemotherapy with ACNU (1 mg/kg) and reserpine (250 micrograms/kg) by intrathecal injection significantly increased the life span of the rats as compared to results with ACNU chemotherapy alone. The enhanced cytotoxicity of ACNU in ACNU-resistant glioma cells in vitro and in vivo may be explained by the increase of intracellular concentration of ACNU resulting from the inhibition of ACNU efflux from the resistant cells by reserpine. It was concluded that ACNU resistance could be modulated in vitro and in vivo by combined therapy with ACNU and reserpine.
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PMID:Modulation in vitro and in vivo of ACNU resistance in a subline of C6 glioma with reserpine. 346 7

One of the serious problems in chemotherapy of brain tumors is that tumor cells are able to acquire resistance to initially effective cytotoxic agents. In order to study the mechanism of this resistance against chemotherapeutic agents, especially ACNU, two variant cell lines (C6/ACNU and 9L/ACNU) resistant to ACNU [1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride] were selected previously in vivo from rat C6 glioma and 9L gliosarcoma, respectively. Uptake and retention of ACNU in these resistant cells were studied with [14C]ACNU. The result indicated that the resistance exhibited by both sublines of C6/ACNU and 9L/ACNU cells were due to the reduced uptake and retention of the drug. The study of the effects of oxidative phosphorylation inhibitor, DNP (2, 4-dinitrophenol), on the uptake and retention of ACNU suggested that there is an active outward transport mechanism for ACNU in 9L/ACNU cells. It might be concluded that ACNU-resistant brain tumor cells are resistant to ACNU by virtue of both the reduced uptake of the drug and the increased active efflux.
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PMID:[Studies on the mechanism of ACNU resistance in sublines of rat C6 glioma and 9L gliosarcoma in vitro]. 346 75

Augmentation of cytotoxicity against cultured human tumor cell lines (5 gliomas, 2 neuroblastomas, 2 sarcomas) using a combination of Aclarubicin (ACR) and Cisplatinum (CDDP) was analysed in vitro from the viewpoints of cell growth inhibition and alteration of the DNA histogram. Synergistic effects of the combination of the two agents were observed in 7 of the 9 cell lines. In sarcoma cell lines, effects were demonstrated even by a low dose of 0.1 microgram/ml CDDP and 0.01 microgram/ml ACR. Flow cytometry studies of the DNA histogram showed increase of accumulation in the S phase following the G2-M phase and reduction of G1 phase cells in response to the combination. From the present experimental studies in vitro, it is concluded that combination chemotherapy with ACR and CDDP may be effective for sarcoma and ACNU-resistant glioma. The mechanism of the synergistic effect produced by the combination is suggested to be impairment of RNA synthesis by ACR which prevents the repair of DNA damage induced by CDDP.
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PMID:[Combination chemotherapy with aclarubicin and cisplatinum against malignant intracranial tumor--an in vitro study]. 346 84


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