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ACNU-cisplatin continuous infusion chemotherapy as salvage therapy for recurrent glioblastomas: phase II study.

PURPOSE: To evaluate the activity and the toxicity of ACNU (1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-cholroethyl)-3-nitrosourea hydrochloride) administered with cisplatin by intravenous infusion for 72 h in select patients with recurrent glioblastoma. PATIENTS AND METHODS: From April 1996 to 2002, 37 patients with histologically proven glioblastoma, who showed recurrence on image study after operation and radiation, met the eligibility criteria of our cohort. The mean time to recurrence was 9.7+/-7.0 (1-26 months). Treatment response was evaluated every 6 weeks using magnetic resonance imaging (MRI). Complete blood counts were collected every week to monitor and treat possible bone marrow suppression from the treatment. Survival rates were analyzed using the Kaplan-Meier and log rank test. RESULTS: Post-chemotherapy MRI was available in 36 of 37 patients. Response to treatment was observed in 19 patients (53%) including two cases of complete remission. Six patients (17%) showed progression (PD) and 11 patients (31%) had stable disease (SD). Two or more cycles of chemotherapy was the only factor that predicted response to treatment. The overall median survival for all patients was 17.0+/-5.5 months. Age (< 40 years) and time to recurrence (>or=1 year) were the clinical factors that predicted improved overall survival. Survival gain after chemotherapy was 9 months. Patients who responded and those with SD after treatment (11 months) had a longer median survival compared to PD (5 months) (P=0.01). Myelosuppression was severe (grade III/IV leukopenia in 15 patients (40%) and grade III/IV thrombocytopenia in 19 patients (52%)) but most recovered more than WHO grade II at the end of the chemotherapy cycles. There was only one fatality due to sepsis from pneumonia during the initial leukopenic state. CONCLUSION: ACNU and cisplatin chemotherapy can be an effective salvage therapy for recurrent glioblastoma patients. Myelosuppression from the chemotherapy regimen was the greatest side-effect but was manageable.

Adolescent↗

Gene expression profiles of 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU)-resistant C6 rat glioma cells.

Chemotherapy in itself is suspected to cause the development or selection of drug-resistant tumor cells, which have more aggressive phenotypes. The authors investigated the differential changes of gene expression in the 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU)-resistant subline of the C6 rat glioma (C6AR2), which was established from C6 rat glioma cells by exposure to ACNU in vitro. The resistance to ACNU of C6AR2 was confirmed by MTS assay. The increased expression of O6-methylguanine-DNA methyltransferase in C6AR2 cells was shown using RT-PCR. C6AR2 cells displayed a higher proliferative activity relative to C6 cells. Analysis with cDNA array showed that 19 genes were transcriptionally up-regulated and 16 genes down-regulated in C6AR2 cells compared to C6 cells. They belonged to various functional classes of genes beside the drug-resistant system. Among them, the down-regulation of several genes in C6AR2 cells, including c-kit, pleiotrophin, platelet-derived growth factor receptor-alpha, peripheral myelin protein-22 and NG2 chondroitin sulfate proteoglycan, which are expressed originally in developmental glial lineages, were verified using semi-quantitative RT-PCR. In addition, the gene expression of astroglial intermediate filament proteins, including GFAP, vimentin and nestin, were decreased in C6AR2 cells relative to C6 cells in semi-quantitative RT-PCR and immunocytochemistry. These findings may represent an undifferentiated state of ACNU-resistant glioma cells and a more aggressive phenotype in recurrent tumors following chemotherapy.

Animals↗

Feasibility and response to 1-(4-amino-2-methyl-5-pyrimidynyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride chemotherapy with pre-treated procarbazine for elderly patients with newly diagnosed glioblastoma.

PURPOSE: To evaluate the feasibility of 1-(4-amino- 2-methyl-5-pyrimidynyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) of pre-treated procarbazine for elderly patients with newly diagnosed glioblastomas. PATIENTS AND METHODS: From January 2004 to March 2005, 7 patients with glioblastoma were enrolled. After maximal surgical resection, patients were treated with two to four cycles of procarbazine (100 mg/m(2) for day 1 to 5), ACNU (80 mg/m(2)/day(1) for day 5), cepharantine (70 mg for day 5 and 12) and vincristine (1.4 mg/m(2) for day 5 and 12). RESULTS: Significant toxicities of this regimen, including infectious toxicities, are described. Among the 7 patients enrolled, there were 6 patients were died, and one was still alive with disease at 13 months. The 6-month progression-free survival and 1-year overall survival are 29% (95% CI, 16% to 73%) and 29% (95% CI, 16% to 73%), respectively. CONCLUSION: The chemotherapy regimen is active but too toxic for elderly patients with newly diagnosed glioblastoma.

Aged↗

Temperature-dependence of cytotoxicity of several genotoxicants in Chinese hamster V79 cells: bleomycin, paraquat, and some N-alkyl-N-nitrosoureas.

Chinese hamster V79 cultured cells were treated with bleomycin (BLM), paraquat (PQ), N-methyl-N-nitrosourea (MNU), and ACNU (an anti-cancer agent) at 30-43 degrees C. The survival fractions normalized by those released from heat-death were plotted vs. the integrated doses of the chemical. Arrhenius analysis of the cell inactivation by the chemical was made. The results revealed that BLM and PQ exerted synergistic cytotoxicity with hyperthermia, whereas MNU and ACNU exerted temperature-dependent cytotoxicities obeying the Arrhenius law.

Animals↗

Interaction of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitroso urea hydrochloride with nucleic acids and proteins.

The binding of the 14C-labelled-ethylene and -pyrimidine moieties of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitrosourea hydrochloride (ACNU) to the biological macromolecules was studied with the AH-130 hepatoma-bearing rats, suspension of AH-130 cells, and isolated nucleic acids and proteins. In all systems examined, a significant level of the binding of the [14C]ethylene of ACNU to nucleic acids, probably due to alkylation, was observed. In contrast, the extent of the binding of the [14C]-pyrimidine was negligible. When a compound lacking the 4-amino group of ACNU (deamino-ACNU) was used for the binding study, relatively higher binding of this compound than that of ACNU to [14C]lysine was observed. It was revealed, therefore, that the low binding of ACNU to proteins could be due to instantaneous depletion of an isocyanate-intermediate, according to the formation of an intramolecularly carbamoylated product with the amino-group on the pyrimidine ring of ACNU molecule during incubation. This could be the molecular basis for the low carbamoylating activity of ACNU in vivo and in vitro, and the antitumor action of ACNU would be dependent on its alkylating activity only.

Animals↗

Comparison of sister-chromatid exchange induction caused by nitrosoureas that alkylate or alkylate and crosslink DNA.

We have investigated the induction of sister-chromatid exchanges (SCEs) in 9L rat brain tumor cells treated with the alkylating agent 1-ethyl-1-nitrosourea (ENU) and 3-(4-amino-2-methyl-5-pyrimidinyl)methyl-1-(2-chloroethyl)-1-nitrosourea (ACNU), an agent that both alkylates and crosslinks DNA. Induction of SCEs by ACNU was found to be 143-fold greater than for ENU. However, on an equimolar basis, the alkylation of DNA by 14C-ACNU was approximately 3.2-fold higher than for 14C-ENU. After correction for this difference was made, the induction of SCEs by ACNU was calculated to be 45-fold greater than for ENU. While DNA alkylation products formed by ACNU and ENU are similar, the chloroethyl alkylation product(s) of ACNU can form DNA-interstrand crosslinks; the ethyl alkylation product(s) of ENU cannot. Based on these findings, we propose that the increased induction of SCEs caused by ACNU is a result of the formation of DNA interstrand crosslinks.

Alkylating Agents↗

Sister-chromatid exchanges (SCEs), cell survival and mutation in HeLa s3 cells with different sensitivity to alkylating agents; evidence that SCE induction and cell survival or mutation induction are dissociable.

We previously isolated N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-resistant cells, MR from HeLa S3 Mer- cells. In the present study, we have isolated 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU)-resistant cells, ACr. The MR cells had only a little O6-methylguanine-DNA methyltransferase (MT) activity, while the ACr cells had increased MT activity and also became resistant to the cytotoxic effect of MNNG. We compared the induction of sister-chromatid exchanges (SCEs), cell survival and mutation in these HeLa S3 cells with different sensitivity to MNNG. The ACr cells were much more resistant than the parental HeLa S3 Mer- cells to cytotoxicity, mutagenicity and SCE induction by MNNG, showing a positive correlation between SCE induction and cell killing or mutation. In contrast, this positive relationship was not observed between HeLa S3 Mer- and MR cells. These results suggest that O6-methylguanine (O6-MeG) is involved in the induction of the biological effects of MNNG such as cytotoxicity, mutagenicity and SCEs, and also indicate that SCE induction does not always correlate with cell killing and mutation.

Alkylating Agents↗

Distribution of intrathecally administered ACNU in mongrel dogs: pharmacokinetics and quantitative autoradiographic study.

The pharmacokinetics of 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) in the cerebrospinal fluid (CSF), were determined in dogs after ventriculolumbar perfusion (VLP, n = 6), and bolus injection into the ventricle (VB, n = 2), cisterna magna (MB, n = 5), and lumbar cistern (LB, n = 3), by high-performance liquid chromatography. The VLP method introduced effective amounts of ACNU into the lumbar cistern for cell kill in vitro. That is, the areas under the time concentration curve (AUC) of ACNU in the lumbar CSF for those receiving a 1.5 mg perfusion of ACNU were 481, 791, and 520 micrograms.min/ml and those receiving a 5 mg perfusion were 1,081, 2,048, and 1,215 micrograms.min/ml, respectively. These values were superior to 3-log cell kill condition of 9L gliosarcoma and 1.5-log cell kill of HU-126 human glioma cell line. Among the groups to which 5 mg of ACNU was administered, the VLP method attained significantly higher AUC values in the lumbar CSF than MB method. Quantitative autoradiography using an imaging plate system was performed in the VLP group (n = 2), VB group (n = 1), MB group (n = 2), and LB group (n = 2) using a 10 microCi/kg [ethylene-14C] ACNU dose which is thought to be related to the alkylating activity of ACNU. The VLP method attained a stable and abundant distribution of ACNU in the neural axis from the ventricular cavity to the lumbar cistern, but the cerebral convexity surface was devoid of a significant level of ACNU. When the MB method was used, the pharmacokinetic data varied in the cisterna magna and lumbar region, and again no significant level of ACNU was detected in the ventricular cavity. With the LB method, although a rich distribution was detected in the spinal cord, the concentration decreased abruptly at the upper cervical level. The VB method was unsatisfactory for obtaining an effective amount of ACNU in the lumbar region. The research and testing to date indicate that the VLP method is the procedure of choice in the treatment of meningeal dissemination.

Animals↗

Chemotherapeutic effects of intra-arterial administration of ACNU in primary intracerebral non-Hodgkin's lymphoma.

The authors report five patients with primary intracerebral non-Hodgkin's lymphoma who were treated with several cycles of intra-arterial injection of 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) at doses of 80 to 100 mg/m2/injection at several monthly intervals. There was no simultaneous use of steroids, and no patients had concomitant immunosuppression; no patient was human immunodeficiency virus positive. This therapy was initially used in four patients with advanced recurrent lymphoma. These patients experienced tumor progression despite our institutional standard therapy comprising cranial irradiation followed by repeated courses of systemic multi-agent chemotherapy (cyclophosphamide, vincristine, adriamycin, and prednisolone) more than 3 months previously. Based upon brain computed tomography scans and clinical neurologic examinations, three of the four cases showed partial responses ranging from 10 to 12 months in duration, whereas the other patient remained stable without worsening for 8 months. A fifth case was particularly noteworthy; this patient had no prior therapy and intra-arterial chemotherapy alone induced an 18-month, disease-free remission. No significant therapy-related complications nor neurotoxicity were seen. These results suggest that intra-arterial administration of ACNU may be a potential candidate for intracerebral lymphoma therapy.

Adult↗

Experimental study of intraoperative local chemotherapy with fibrin glue containing nitrosourea for malignant gliomas.

BACKGROUND: Local control of the tumor bed after removal of a tumor is one of the most important points in the treatment of malignant gliomas. This study was designed to examine whether fibrin glue is useful as a vehicle for sustained release of intraoperative local chemotherapy with nitrosourea (ACNU). METHODS: The growth-inhibiting activity of ACNU on C6 glioma cells and ACNU released into 5-mL supernatant saline from fibrin glue containing 5 mg/mL (10 mg) of ACNU was measured in vitro. C6 tumor inoculated in rat brains was covered with fibrin glue containing either 2 mg/mL or 5 mg/mL of ACNU for 5 days, and the histologic changes were examined. RESULTS: ACNU inhibited the growth of C6 glioma cells in a dose-dependent manner, and the drug concentration required for 50% inhibition of cell growth (IC50) was about 4 micrograms/mL with 1 hour of treatment. Although about 50% of all ACNU included in the fibrin glue was released in the first hour, an effective concentration over the value of IC50 was sustained even after 12 hours. A histologic examination showed tumor cells damaged within a depth of about 2-3 mm from the tumor surface covered with fibrin glue containing ACNU. CONCLUSIONS: Fibrin glue may be useful as a vehicle for sustained-release chemotherapy, and intraoperative local chemotherapy with fibrin glue containing anticancer agents such as nitrosourea may be helpful in the local control of malignant gliomas.

Animals↗

A comparison of intraarterial carboplatin and ACNU for the treatment of gliomas.

BACKGROUND: Intraarterial chemotherapy with carboplatin for malignant gliomas has been tried recently, but its therapeutic efficacy and toxicity have not yet been elucidated. METHODS: We treated patients with malignant glioma by intraarterial chemotherapy using carboplatin, and compared the efficacy as well as the side effects with intraarterial ACNU. RESULTS: Twenty patients were treated with carboplatin (300 mg/m2) and 22 patients were treated with ACNU (80-200 mg/m2). Response (complete remission+partial response) rate for carboplatin was 12.5% compared to 45% for ACNU. Despite higher response rate for ACNU, the difference in the survival curves of the two groups was not significant. Three patients who were treated with high dose (150-200 mg/m2) of ACNU developed hemiparesis and aphasia. Seven patients treated with carboplatin developed 10 incidences of neurotoxicities; two hemiparesis, one aphasia, one blindness, one visual field disturbance, three convulsions, and two developed incidences of disturbances of consciousness. CONCLUSIONS: Intraarterial carboplatin was not superior to intraarterial ACNU in achieving remissions, and showed much greater tendency to produce neurotoxicities.

Adolescent↗

Augmentation of the radiation-induced antiproliferative effect in combined use of a derivative of nitrosourea, ACNU, with recombinant human tumor necrosis factor.

The effect of combined use of a derivative of nitrosourea, ACNU, with recombinant human tumor necrosis factor (rhTNF) on the radiation-induced antiproliferative effect was examined using Meth A tumor cells. The radiation-induced antiproliferative effect was slightly augmented by the simultaneous addition of ACNU at 10 micrograms/ml in 5 Gy and 15 Gy irradiated groups. The antiproliferative effect was augmented in parallel with the radiation dose by the addition of rhTNF. Further augmentation of the proliferation inhibition was observed when both of ACNU (10 micrograms/ml) and 10 U/ml of rhTNF were added in combination with irradiation. Similar augmentation was observed when the target cells were treated with ACNU prior to irradiation and the addition of rhTNF.

Animals↗

Difference in O6-methylguanine methyltransferase activity among transformed NIH3T3 cell clones.

We examined the sensitivity to the lethal effects of methylating agents and the O6-methylguanine methyltransferase (MTR) activities of in vitro transformed NIH3T3 cell clones. The sensitivities to the lethal effects of MNNG were not different among all 49 transformed cell clones examined and do not correlate with the MTR activities. All 8 spontaneously transformed cell clones showed the same sensitivities to ACNU as the parental cell line. 2 of 20 transformants induced by UV or MNNG showed higher sensitivities to the ACNU although the MTR activity was normal. One cell clone transformed by UV was sensitive to ACNU and showed about half MTR activity. 5 of 19 cell clones transformed by oncogenes (Ha-ras or SV40 ori-) were sensitive to the lethal effects of ACNU and showed the low MTR activities, but were not as much sensitive as a Ha-MuSV transformed cell clone, Ha821.

Animals↗

Instability of Mex- phenotype in human lymphoblastoid cell lines.

Three lymphoblastoid cell lines (LCLs) had extremely low activities of O6-alkylguanine-DNA alkyltransferase (O6-AGT), and were classified as Mex-. They were highly sensitive to cell killing by 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosoure a hydrochloride (ACNU), whereas NMO2, a Mex+ LCL with a high O6-AGT activity, was resistant to the agent. Small fractions of these Mex- LCLs survived the treatment with 10 micrograms/ml of ACNU for 24 h, and the surviving cells were found to be resistant to subsequent treatments with the agent. In addition, they contained O6-AGT activities comparable to that of NMO2 and were therefore regarded as Mex+. These results suggest that the Mex- phenotype in LCLs is unstable.

Cell Division↗

Comparative analysis of O6-methylguanine methyltransferase activity and cellular sensitivity to alkylating agents in cell strains derived from a variety of animal species.

Using 26 cultured cell lines derived from 17 different animal species, we have measured both the activity of O6-methylguanine (O6-MeG) methyltransferase (MT) in cell extracts and the sensitivity of the strains to the lethal effects of the alkylating agents, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU). The MT activity was assayed by measuring the amount of 3H radioactivity transferred from methyl-[3H]-labeled O6-MeG in DNA to acceptor protein molecules in the extracts. In all the 21 mammalian cell strains, lethal sensitivity to ACNU as measured by colony-forming ability correlated well with cellular MT activity, indicating that the major lethal ACNU damage is reparable by the MT. On the other hand, MNNG sensitivity did not necessarily correlate with the MT activity.

Alkylating Agents↗

Augmented anti-proliferative effect in combined use of human lymphotoxin with a nitrosourea derivative, ACNU, and the involvement of glutathione redox cycle.

The cytotoxic or cytostatic effect of the combined use of human lymphotoxin (LT) with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3- nitrosourea hydrochloride (ACNU) on L cells or Meth A tumor cells was studied. Simultaneous addition of LT derived from a human lymphoid cell line with ACNU (200 or 500 micrograms/ml) significantly augmented the cytotoxic effect. Similar augmented inhibition was obtained when LT was added to ACNU-treated L cells. The pre-treatment of Meth A tumor cells with ACNU (25 or 50 micrograms/ml) augmented recombinant human LT-mediated cytostasis. However, the addition of glutathione (1.0 mg/ml) to ACNU-treated Meth A tumor cells significantly nullified the augmented anti-proliferative effect of LT (10 U/ml). These results suggest that augmentation of the anti-proliferative effect on tumor cells could be induced through the combined use of LT with ACNU by lowering the intracellular level of glutathione.

Animals↗

Effects of ACNU, a water-soluble nitrosourea derivative, on survival and cell kinetics of cultured HeLa S3 cells.

Effects of a water-soluble nitrosourea, 1(4-aminomethylpyrimidine-5yl)methyl-3-(2-chloroethyl)-3-nit rosourea hydrochloride (ACNU) was investigated on cultured HeLa S3 cells with regard to their lethality and cell progression through the cell cycle. The survival curve of exponentially growing cells exposed to increasing concentrations of the drug for 1 hr was characterized by a threshold type of response (Do = 7.0 micrograms/ml X 1 hr, Dq 3.5 micrograms/ml X 1 hr). Throughout the cell cycle, ACNU exerted its main killing effect on cells in the G1 and G2 + M phases, whereas cells in S were resistant to the drug. The change in their age-response was due to the Do value of the dose-survival curve rather than the Dq. Effects of cell progression were also examined at a low concentration of ACNU (5.0 micrograms/ml), which allowed 80% of treated cells to survive. Delayed transit was observed in the S phase, and more markedly in the G2 + M phase. The magnitude of these perturbations depended on the position of the cell cycle at which the drug was administered. Cells treated in the G1 and early S phases showed a much longer duration of S and G2 + M phases than cells treated in mid-S phase. Cells treated in the late S and G2 phases could normally pass through mitosis, but were subsequently blocked in the G2 phase following a prolonged S phase in the next cell cycle. These studies revealed that there seems to be some positive relationship of the effect of ACNU on cell progression and cell killing throughout the cell cycle.

Cell Cycle↗