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Ovarian function following chemotherapy for childhood brain tumours.

Pubertal development, basal gonadotrophin, and oestradiol levels were assessed in 21 girls who had received neuroaxis irradiation for a brain tumour followed by adjuvant chemotherapy with carmustine (BCNU) or lomustine (CCNU) and procarbazine. Thirteen received chemotherapy before the age of 11 years. Ten remained prepubertal at their last assessment, nine of whom showed biochemical evidence of primary ovarian failure. The remaining three were pubertal or adult, and although basal follicle-stimulating hormone (FSH) and luteinising hormone (LH) levels were normal, all had shown abnormalities of gonadotrophin secretion previously. Eight girls received chemotherapy after 11 years of age. Only three girls exhibited an elevated basal FSH level or exaggerated FSH response to GnRH. Elevated basal FSH values had been noted previously in two of the other five girls. All girls entered or progressed through puberty spontaneously. Seven experienced menarche at an appropriate age. However in four, gonadotrophin levels, which had been elevated, were now within the normal range. In two, menses had continued throughout with normal midfollicular oestradiol levels, whilst the other two developed secondary amenorrhoea associated with radiation-induced gonadotrophin deficiency. The majority of girls showed evidence of primary ovarian dysfunction. This did not prejudice pubertal development or the timing of menarche. Ovarian function may return to normal in the years after treatment, indicating a potential for fertility.

Adolescent↗

Intermittent interferon and polychemotherapy in metastatic melanoma.

This study was conducted to evaluate the efficacy and the tolerability of a four-drug chemotherapy regimen combined with interferon alpha (IFN) in metastatic melanoma. Between March 1991 and August 1993, 55 patients with advanced melanoma were enrolled for the present multicentre phase II study. Forty-nine patients were eligible and evaluable for toxicity; 48 patients were evaluable for response. The treatment schedule consisted of a 5-day regimen of dacarbazine, vincristine, bleomycin and lomustine, plus 6 x 10(6) IU IFN alpha three times weekly subcutaneously for 2 weeks starting on day 8. The cycle was repeated on day 29. Among the 48 assessable patients, 16 objective responses were seen, yielding a response rate of 33% (95% confidence interval 20%-46%). Seven patients achieved a complete response (CR) of a median of 6+ months (range 1+ to 21+ months) and 9 patients achieved a partial response (PR) of a median of 9 months (range 4-13 months). The median overall survival was 12+ months (range 6+ to 23+ months) for the patients with CR and 15+ months (range 8-20 months) for the patients with PR. Even the survival of the 7 patients with stable disease was fairly long (median 12, range 7-17 months), appearing to be significantly longer than the survival of the 25 patients with progressive disease (median 5, range 1-24+ months). The treatment was moderately well tolerated, although all patients experienced some mild form of toxicity, mostly gastrointestinal symptoms, neurotoxicity and haematotoxicity. Grade 3-4 adverse effects were noted in 39% of the patients. No toxic deaths occurred. It can be concluded that the present regimen produces meaningful responses for patients with metastatic melanoma. A randomised study is needed to determine the effect on survival.

Adult↗

Pharmacokinetics of high-dose oral CCNU in bone marrow transplant patients.

PURPOSE: CCNU (lomustine) and other nitrosourea compounds are rapidly metabolized to alkylating moieties, which are active against various malignancies. In humans, CCNU undergoes biotransformation to the geometric isomers of 4'-hydroxyCCNU. The pharmacokinetics of trans-and cis-4'-hydroxyCCNU were determined in five patients with Hodgkin's or non-Hodgkin's lymphoma receiving sequential doses of CCNU (15 mg/kg), etoposide (60 mg/kg) and cyclophosphamide (100 mg/kg) prior to autologous bone marrow transplantation. METHODS: Plasma concentrations of the isomeric forms of the metabolites were determined by high-performance liquid chromatography. Data were analysed using noncompartmental pharmacokinetic methods. RESULTS: Formation of the trans-isomer predominated over that of the cis-isomer, with an average exposure ratio of 1.4 (range 1.0-2.1). Peak plasma concentrations occurred between 1 and 4.1 h postdosing and averaged 1.56 mg/l for the trans-isomer and 1.10 mg/l for cis isomer. Peak plasma concentrations and systemic exposures varied approximately six- and ninefold, respectively, reflecting significant interindividual variability in alkylating activity after high doses of CCNU. Plasma half-lives of the metabolites were 3.1 h (range 1.1-4.5 h) for the trans-isomer and 3.5 h (range 1.3-6.4 h) for the cis- isomer, and varied linearly with increasing patient body weight. There was no significant difference in plasma half-lives after high-dose CCNU administration observed in this study and those reported previously after the administration of substantially lower doses of CCNU. CONCLUSION: Despite linearity in the pharmacokinetics of the isomeric forms of 4'-hydroxyCCNU at high doses, large interindividual variability in exposure to the CCNU metabolites was observed. Potential saturation of metabolic pathways to the isomers at these doses may manifest as toxic symptoms since alkylating moieties formed directly from the parent, CCNU, may be associated with greater toxicity than those formed from the isomeric forms of the 4'-hydroxylated metabolite.

Administration, Oral↗

A role for preirradiation PCV chemotherapy for oligodendroglial brain tumors.

Oligodendroglial tumors have been identified as a subgroup of glial neoplasms with a distinctly better response to chemotherapy and overall survival than purely astrocytic gliomas. Here we report our experience with adjuvant postirradiation and preirradiation chemotherapy using procarbazine, lomustine, and vincristine (PCV) in 27 patients with WHO grade II or III oligodendroglioma or oligoastrocytoma. The efficacy of chemotherapy was assessed according to the Macdonald response criteria (complete response, CR; partial response, PR; stable disease, SD; progressive disease, PD) and progression-free survival intervals by computed tomography or magnetic resonance imaging. First, we confirm that PCV salvage therapy for patients progressing after radiotherapy is highly effective (n = 11, 1 CR, 5 PR, 5 SD; median progression-free survival has not yet been reached, but is longer than 18 months). Second, 3 patients who received radiotherapy plus PCV as first-line therapy achieved CR and 2 achieved SD, and all 5 are progression-free with a median follow-up of 12 months. Third, given these encouraging results, 11 patients received postoperative preirradiation PCV chemotherapy and were given radiotherapy only upon progression. Preirradiation PCV chemotherapy was also effective (2 CR, 3 PR, 6 SD; median progression-free survival has not been yet reached, but is longer than 14 months). Patients with anaplastic oligoastrocytomas were as likely to respond to PCV chemotherapy, as were patients with anaplastic oligodendroglioma. Three patients who had previously responded to PCV were successfully treated with a second course of PCV upon recurrence. PCV chemotherapy was also effective in patients with leptomeningeal spread of oligodendrogliomas. A randomized prospective trial is required to compare the effectiveness and neurotoxicity of first-line PCV chemotherapy followed by radiotherapy to the traditional reverse sequence.

Adolescent↗

Genotoxic effect of 4-aroyl-1-(2-chloroethyl)-1nitrosohydrazinecarboxamides on Saccharomyces cerevisiae cells.

The study of some 4-aroyl-1-(2-chloroethyl)-1-nitrosohydrazinecarboxamides with a Saccharomyces cerevisiae mutagenicity test of increased sensitivity defined two of them, 4-(4-bromobenzoyl)-1-(2-chloroethyl)-1-nitrosohydrazinecarboxam ide and 4-(4-fluorophenyl)-1-(2-chloroethyl)-1-nitrosohydrazine carboxamide as typical cytostatic agents. At concentrations of 2-5 microg/ml the substances kill up to 60%-70% of cells without having any detectable recombinogenic and mutagenic effects. At the same concentrations, lomustine, well known as a cytostatic reference, demonstrated recombinogenic and mutagenic activity on yeast cells. The advantage of the newly synthesized substances is that, in a certain concentration range, their biological activity is mainly cytotoxic without induction of recombinogenic and mutagenic events in surviving cells.

Antineoplastic Agents↗

Locally delivered chemotherapy and repeated surgery can improve survival in glioblastoma patients.

We treated 54 patients, newly diagnosed for glioblastoma, with systemic chemotherapy (carmustine (BCNU) 100 mg/m2 and cisplatin 90 mg/m2 every 6 weeks) and radiotherapy soon after surgery. In 10 cases the treatment was combined with locoregional chemotherapy (1 mg bleomycin on days 1-2, and 3 mg mitoxantrone on day 3, repeated every 20 days) administered from an Ommaya reservoir. At tumor recurrence, all patients were treated with procarbazine, lomustine and vincristine (PCV); 15 of 54 were reoperated and treated with locoregional chemotherapy. The median time to disease progression (TTP) and overall survival time (ST) for the whole group were 10.8 and 23.1 months, respectively. The ST of the 15 reoperated patients who also received locoregional treatment at disease recurrence was 27.6 months; this was significantly longer than that of patients not reoperated and not treated locally (log-rank p=0.04). The results in our reoperated subgroup support the opinion that a second operation could be suitable if it is part of the whole program of treatment.

Antineoplastic Combined Chemotherapy Protocols↗

Treatment of advanced Hodgkin's disease with chemotherapy and irradiation. Controlled trial of two versus three alternating, potentially non-cross-resistant drug combinations.

From January 1979 to June 1983, 71 evaluable, previously untreated patients with advanced Hodgkin's disease completed a randomized trial of two or three potentially non-cross-resistant drug combinations and low-dose radiotherapy to initially involved nodal regions (2,000 to 3,000 rads). All patients received nine cycles of alternating chemotherapy regimens and radiotherapy between cycles 6 and 7. Thirty-four patients received three combinations: lomustine, melphalan, vindesine (CAD), MOPP, and doxorubicin, bleomycin, vinblastine (ABV). The complete remission rate was 82 percent, partial remission rate 12 percent, and progression rate 6 percent. There were two relapses from complete remission and three deaths. Thirty-seven patients received MOPP and ABV plus dacarbazine (D). The complete remission rate was 78 percent, partial remission rate 16 percent, and progression rate 6 percent, with three relapses from complete remission and five deaths. Myelosuppression was more frequent with CAD/MOPP/ABV/radiotherapy, and nausea and vomiting with MOPP/ABVD/radiotherapy. The results for both are among the best reported, and CAD/MOPP/ABV/radiotherapy was more acceptable to patients.

Adolescent↗

Human liver microsomal cytochrome P450 3A isozymes mediated vindesine biotransformation. Metabolic drug interactions.

Vindesine biotransformation was investigated using a bank of human liver microsomes. The drug was converted into one major metabolite (M) upon incubation with the microsomes. Large interindividual variations were observed: vindesine biotransformation rates ranged from 1.2 to 12.9 pmol/min/mg protein. Vindesine metabolic processes followed Michaelis-Menten kinetics: Km = 24.7 +/- 9.4 microM, Vmax = 1.5 +/- 0.8 nmol/min/mg protein. The involvement of human cytochrome P450 3A isozymes in vindesine metabolism was demonstrated by: (1) competitive inhibition of vindesine biotransformation by compounds known to be specifically metabolized by human cytochrome P450 3A. Apparent Ki values were 3.6, 17.9 and 19.8 microM for quinidine, troleandomycin and erythromycin, respectively; (2) immunoinhibition of vindesine metabolism by polyclonal anti-P450 3A antibody; (3) significant correlation between immunoquantified P450 3A and vindesine biotransformation (r = 0.800, P < 0.001); and (4) significant correlation between erythromycin N-demethylase activity, which was supported by P450 3A in humans, and vindesine biotransformation (r = 0.853, P < 0.001). Other vinca alkaloids also exerted an inhibitory effect on vindesine biotransformation with apparent Ki values of 3.8, 10.6 and 19.2 microM for vinblastine, vincristine and navelbine, respectively, suggesting a possible involvement of the same cytochrome subfamily in their hepatic metabolism. Moreover, a number of anticancer drugs currently associated with the vinca alkaloids, such as teniposide, etoposide, doxorubicin, lomustine, folinic acid and mitoxantrone, significantly inhibited vindesine biotransformation.

Adult↗

Radiotherapy alone versus combined chemotherapy and radiotherapy in unresectable non-small cell lung carcinoma.

We report the results observed in a large randomized study comparing radiotherapy alone to combined radiotherapy and chemotherapy in unresectable squamous cell and large cell lung carcinoma. Radiation dose was 65 Gy in both groups and chemotherapy included vindesine, cyclophosphamide, cisplatin and lomustine. One hundred seventy-seven patients received radiotherapy alone, and 176 received the combined treatment. The 2-year survival rate was 14% for patients receiving radiotherapy vs. 21% for patients receiving the combined treatment (P = 0.02). The distant metastasis rate was significantly lower in the group receiving the combined treatment (P < 0.001). Local control at 1 year was poor in both groups (17% and 15%, respectively) and remains a major problem in locally advanced non-small cell lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗

A randomized clinical trial comparing systemic radiotherapy versus chemotherapy versus local radiotherapy in small cell lung cancer.

Between 1982 and 1987 a prospectively randomized trial of sequential hemibody irradiation (SHBI) (A), a non-cross-resistant chemotherapy drug combination (B) and local and/or locoregional radiotherapy (C) in small cell lung cancer (SCLC) was conducted. Previously untreated patients with extensive SCLC were randomized into three arms: A = 31 patients, B = 37, C = 31. In the chemotherapy combination, the following were used: etoposide, doxorubicin, methotrexate (VAM) and procarbacine, vincristine, cyclophosphamide, lomustine (POCC) and prophylactic cranial irradiation (30 Gy). The results show that the median survival was significantly (P less than 0.01) better in chemotherapy (44 weeks) compared with 17 and 20 weeks in arms A and C, respectively. One year and 2 year survival rates were better for the chemotherapy arm. No differences were found between groups A and C. In comparing the total hospitalization time expressed as a percentage of overall survival, an advantage for group B was shown. In conclusion, high dose SHBI cannot be recommended as a standard therapy for extensive SCLC.

Antineoplastic Combined Chemotherapy Protocols↗

Superiority of post-radiotherapy adjuvant chemotherapy with CCNU, procarbazine, and vincristine (PCV) over BCNU for anaplastic gliomas: NCOG 6G61 final report.

Data from Northern California Oncology Group protocol 6G61, which was closed in February 1983, were reanalyzed in December 1988. The protocol called for a randomized trial that compared the effects of following 60 Gy radiation/oral hydroxyurea treatment with either carmustine (BCNU) or the combination of procarbazine, lomustine (CCNU), and vincristine (PCV) for two histologic strata: glioblastoma multiforme and other anaplastic gliomas. PCV produced longer survival and time to tumor progression than BCNU for both histologic groups, although the difference was statistically significant only for the anaplastic gliomas. With PCV treatment, time to progression and survival doubled for anaplastic glioma patients in the 50th and 25th percentiles.

Adult↗

ASTRO (American Society for Therapeutic Radiology and Oncology) plenary: Effect of chemotherapy on locally advanced non-small cell lung carcinoma: a randomized study of 353 patients. GETCB (Groupe d'Etude et Traitement des Cancers Bronchiques), FNCLCC (Féderation Nationale des Centres de Lutte contre le Cancer) and the CEBI trialists.

Most patients with locally advanced non small cell lung carcinoma are treated with external thoracic radiotherapy. Because of the high incidence of distant metastasis the addition of chemotherapy has been proposed. The present randomized study was conducted from June 1983 to February 1989 and included 353 patients. The trial compared arm A, thoracic megavoltage radiotherapy alone at a total dose of 65 Gy in 26 fractions and 45 days, to arm B that comprised the same radiotherapy preceded and followed by 3 monthly cycles of VCPC (vindesine 1.5 mg/m2 d 1-2, cyclophosphamide 200 mg/m2 d 2-4, cisplatinum 100 mg/m2 d 2 and lomustine 75 mg/m2 d 3). Disease was deemed unresectable but non-metastatic after bronchoscopic, radiologic, CAT, and nuclear scans and physical examinations. Only patients in clinical, radiological, endoscopic, and histological complete remission were considered as locally controlled; these patients were monitored by fiberoptic bronchoscopy and systematic biopsies to the primary site. One hundred seventy-seven patients received thoracic radiotherapy alone and 176 received the combined modality. Twenty-seven percent of arm B patients had an objective response after 2 VCPC cycles. At the time of final assessment, performed 3 months after the end of thoracic radiotherapy in both arms, there were 20% of complete responders in arm A versus 16% in arm B. The two-year survival rate was 14% in arm A versus 21% in arm B (p = 0.08, logrank test). The distant metastasis rate was 67% in arm A versus 45% in arm B (p less than 0.001). Local control at 1 year was poor in both groups (17% and 15%, respectively). The striking effect of VCPC chemotherapy on the incidence of distant metastasis did not have a significant impact on overall survival. We conclude that thoracic tumor control remains a significant problem in unresectable non small cell lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗

External irradiation followed by an interstitial high activity iodine-125 implant "boost" in the initial treatment of malignant gliomas: NCOG study 6G-82-2.

Between January 1982 and January 1990, 107 patients with unifocal, circumscribed malignant gliomas participated in a non-randomized trial testing brachytherapy in their initial treatment. Focal external irradiation (6000 cGy) was combined with an implant of high-activity iodine-125 (5000-6000 cGy) and six courses of procarbazine, lomustine, and vincristine. Of the 101 evaluable patients, 63 received implants. Of these, 29 had non-glioblastoma anaplastic gliomas, and 34 had glioblastoma multiforme. The other 38 did not receive implants, in most cases because radiation therapy failed to reduce the size of the tumor. The median survival was 165 weeks for all evaluable patients with non-glioblastoma anaplastic gliomas, 157 weeks for those with implants, 67 weeks for all evaluable glioblastoma patients, and 88 weeks for those with implants. Of the glioblastoma patients with implants, nine were alive after 2 years, and three were alive after 3 years. In each of the groups, nearly half the patients underwent reoperation for clinical deterioration, increasing steroid dependency, and increasing mass effect at the implantation site after 46.1 weeks (median) for glioblastoma multiforme and 41.3 weeks for non-glioblastoma patients. Karnofsky Performance Scores showed only a small decline in performance after brachytherapy. Patients receiving implants for non-glioblastoma anaplastic gliomas had a mean Karnofsky Performance Score of 91% (range 90-100%) after 1 month and 78% (range 60-100%) 30 months after brachytherapy. Those treated for glioblastoma multiforme had a mean Karnofsky Performance Score of 86% (range 60-100%) at 1 month and 75% (range 60-100%) at 24 months. The quality of life of treated patients appears to be satisfactory. On the basis of comparisons with previous studies, we conclude that a brachytherapy "boost" after external irradiation may be valuable for some patients with glioblastoma multiforme but not for those with non-glioblastoma anaplastic gliomas.

Adult↗

Phase II study of accelerated fractionation radiation therapy with carboplatin followed by vincristine chemotherapy for the treatment of glioblastoma multiforme.

PURPOSE: To conduct a Phase II one-arm study to evaluate the long-term efficacy and safety of accelerated fractionated radiotherapy combined with intravenous carboplatin for patients with previously untreated glioblastoma multiforme tumors. METHODS AND MATERIALS: Between 1988 and 1992, 83 patients received 1.9-2.0 Gy radiation three times a day with 2-h infusions of 33 mg/m2 carboplatin for two 5-day cycles separated by 2 weeks; following radiotherapy, patients received procarbazine, lomustine (CCNU), and vincristine (PCV) for 1 year or until tumor progressed. RESULTS: Eighty-three patients were evaluable for analysis. Seventy-four of the 83 patients (89%) received one or more courses of PCV; their median survival was 55 weeks. Total resection was performed in 20% (15 of 74), subtotal resection in 69% (51 of 74), and biopsy in 11% (8 of 74); reoperation (total or subtotal resection) was performed in 28 patients (37%). Survival was worst for those > or = 61 year old (median 35 weeks). Fits of the Cox proportional hazards regression model showed covariates individually predictive of improved survival were younger age (p < 0.01), smaller log of radiation volume (p = 0.008), total or subtotal resection vs. biopsy (p = 0.056), and higher Karnofsky performance status (p = 0.055). A multivariate analysis showed that age (p = 0.013) and extent of initial surgery (p = 0.003) together were predictive of a better survival with no other variables providing additional significance. Only 8.4% (7 of 83) of patients had clinically documented therapy-associated neurotoxicity ("radiation necrosis"). CONCLUSION: When comparable selection criteria were applied, the survival in this study is similar to the results currently attainable with other chemoradiation approaches. The relative safety of accelerated fractionated radiotherapy, as used in this study with carboplatin, enables concomitant full-dose administration of chemotherapy or radiosensitizing agents in glioblastoma multiforme patients.

Adult↗

Updated results of a pilot study of low dose craniospinal irradiation plus chemotherapy for children under five with cerebellar primitive neuroectodermal tumors (medulloblastoma).

PURPOSE: Children under 5 years old with medulloblastoma (MB) have a poor prognosis. They are more susceptible to the deleterious effects of craniospinal irradiation (CSART) and have a higher relapse rate when treated with low-dose CSART alone. We, thus, embarked on a prospective trial testing the usefulness of very low dose CSART and adjuvant chemotherapy. This is an update of a previous report on these patients. METHODS AND MATERIALS: Between January 1988 and March 1990, 10 patients with medulloblastoma were treated using 18 Gy radiation therapy (RT) to the craniospinal axis, a posterior fossa (PF) boost to 50.4-55.8 Gy and chemotherapy consisting of vincristine (VCR) weekly during RT. This was followed by VCR, cis-diamminedichloroplatinum (CDDP), and lomustine (CCNU) for eight, 6-week cycles. Patients between 18 and 60 months of age without evidence of tumor dissemination were eligible for study. Follow-up was available until September 1994 with a median follow-up for living patients of 6.3 years from diagnosis. RESULTS: Actuarial survival at over 6 years is 70 +/- 20%. Three of the 10 patients relapsed and died. In one patient, the relapse developed in the spine and brain outside the posterior fossa, in the second, concurrently in the posterior fossa, brain and spine, and the third, only in the spine. One surviving child developed a brain stem infarct 4.8 years after diagnosis and has since almost fully recovered. A mean intelligence quotient (IQ) score of 103 in six patients surviving at least 1 year is unchanged from the baseline group score of 107. Five children tested at baseline and 2 years following treatment had IQ scores of 101 and 102, respectively. Six children tested at baseline and at 3 years had IQ scores of 106 and 96, respectively. Excluding the child tested shortly after his brain stem infarct, baseline and 3 year IQ scores were 103 and 97, respectively. Five of the seven long-term survivors grew at rates significantly below their expected velocities during the follow-up period, while the others grew normally. Three patients have received growth hormone, and none have required thyroid replacement. CONCLUSIONS: These data suggest that medulloblastoma patients can be cured with chemotherapy and reduced doses of craniospinal irradiation. The low doses of CSART given by us in conjunction with cis-platin-based chemotherapy produce minimal neurocognitive damage. Growth velocities in very young children so treated are, however, dramatically reduced. Better means of improving the therapeutic ratio are still needed.

Age Factors↗

Survival of adults treated for medulloblastoma using paediatric protocols.

We retrospectively studied 26 consecutive adults treated for medulloblastoma using paediatric protocols. Between 1987 and 2003, patients 18 years old were given adjuvant chemotherapy consisting of one of two 'paediatric' regimens (depending on the time of presentation) and craniospinal local-boost radiotherapy: regimen A (n = 12), vincristine (VCR), intrathecal and/or intravenous methotrexate and conventional radiotherapy; or regimen B (n = 11) sequencing intensive doses of multiple agents followed by hyperfractionated accelerated radiotherapy (HART). A VCR-lomustine-based maintenance followed both regimens. Three additional patients received a tailored treatment due to their impaired neurological status after surgery. The median age at diagnosis was 26 years (range 18-41 years). With a median follow-up of 46 months, 5-year disease-free and overall survival rates were 65+/-11% and 73+/-10%, respectively, for the series as a whole. All patients who received regimen B (5 of whom had metastatic Chang M2-M3 disease) are alive with no evidence of disease at 39 months. Although the number of patients is limited, our data suggest that the sandwich sequential, moderately intensive chemotherapy in combination with HART is an effective treatment for medulloblastoma in adults, and this approach seems to overcome previously-recognised risk factors.

Administration, Oral↗

Poly(ADP-ribose) polymerase-independent potentiation of nitrosourea cytotoxicity by 3-aminobenzamide in human malignant glioma cells.

Poly(ADP-ribose) polymerase is a zinc-finger DNA-binding protein that detects specifically DNA strand breaks generated by genotoxic agents and is thought to be involved in DNA repair. Here, we examined the effects of 3-aminobenzamide, a poly(ADP-ribose) polymerase inhibitor, on the chemosensitivity of human malignant glioma cells. 3-Aminobenzamide selectively potentiated the cytotoxicity of the nitrosoureas, nimustine, carmustine and lomustine in 10 of 12 human malignant glioma cell lines. In contrast, 3-aminobenzamide did not modulate the cytotoxic effects of doxorubicine, teniposide, vincristine, camptothecin or cytarabine. The nitrosoureas did not induce poly(ADP-ribose) polymerase activity in the glioma cells. Ectopic expression of truncated poly(ADP-ribose) polymerase containing the poly(ADP-ribose) polymerase DNA-binding domain, which acts as a dominant-negative mutant, in LN-18 or LN-229 cells did not alter the 3-aminobenzamide effect on nitrosourea-mediated cytotoxicity. Thus, 3-aminobenzamide may target another nicotinamide adenine dinucleotide (NAD)-requiring enzyme, but not poly(ADP-ribose) polymerase, when enhancing nitrosourea cytotoxicity in human malignant glioma cells. Carmustine cytotoxicity was associated with a G2/M arrest. Coexposure to carmustine and 3-aminobenzamide overcame this G2/M arrest in T98G cells, which are sensitized to carmustine by 3-aminobenzamide, but not in U251MG cells, which are refractory to 3-aminobenzamide-mediated sensitization to carmustine. Thus, 3-aminobenzamide-mediated sensitization to carmustine cytotoxicity may result from interference with the stable G2/M arrest response to carmustine in human glioma cells.

Benzamides↗