High-grade Gliomas In Children Research Articles

Therapeutic efficacy of vinorelbine against pediatric and adult central nervous system tumors.

The activity of vinorellbine, a new semisynthetic vinca alkaloid, was evaluated against a battery of human tumor xenografts derived from adult and pediatric CNS malignancies. Tumors included adult high-grade gliomas (D-54 MG, D-245 MG), childhood high-grade gliomas (D-212 MG, D-456 MG), medulloblastomas (D-341 MED, D-487 MED), ependymomas (D-612 EP, D-528 EP), and a mismatch repair-deficient procarbazine-resistant glioma [D-245 MG (PR)]. Tumors were grown subcutaneously in athymic nude mice and vinorelbine was administered at a dose of 11 mg/kg on days 1, 5, and 9. Additionally, vinorelbine was also administered in combination with BCNU against D-54 MG. Vinorelbine produced statistically significant growth delays in D-456 MG, D-245 MG, and D-245 MG (PR). No statistically significant growth delays were observed in D-54 MG, D-487 MED, D-212 MG, D-528 EP, D-341 MED or D-612 EP. The antitumor effects of the vinorelbine/BCNU combination were additive. Growth delays observed in the procarbazine-resistant line [D-245 MG (PR)] were greater than twofold the delays seen in the parent line (D-245 MG). Vincristine was equally potent against D-245 MG and D-245 MG (PR). Taxol demonstrated little activity against D-245 MG but produced 32- and 18-day growth delays in D245 MG (PR). These studies indicate that vinorelbine possesses antitumor activity against several glioma tumor xenografts with marked activity in a mismatch repair deficient-tumor.

Characterization of the mechanisms of busulfan resistance in a human glioblastoma multiforme xenograft.

Busulfan is an alkylating agent commonly used in the treatment of chronic myelogenous leukemia and in combination with cyclophosphamide in preparation for allogeneic bone marrow transplantation. Serial treatment of a childhood high-grade glioma xenograft (D-456 MG) with busulfan resulted in a busulfan-resistant xenograft, D-456 MG(BR). Cross-resistance to 1,3-bis(2-chloroethyl)-1-nitrosourea was seen but not resistance to cyclophosphamide or CPT-11. Cytoplasmic levels of glutathione in D-456 MG(BR) were approximately one-half those found in D-456 MG. This depletion could not be explained by levels of glutathione-S-transferase, or by amplification, rearrangement, or increased levels of transcript of gamma-glutamylcysteine synthetase. Furthermore, depletion of glutathione in D-456 MG did not alter busulfan activity. Quantitation of busulfan levels in D-456 MG and D-456 MG(BR) xenografts following treatment of mice at the dose lethal to 10% of the animals demonstrated that significantly lower levels of drug were achieved in D-456 MG(BR). These studies suggest that alterations in drug transport or metabolism of busulfan may play a role in the resistance of D-456 MG(BR) to this alkylator.

Therapeutic efficacy of the topoisomerase I inhibitor 7-ethyl-10-(4-[1-piperidino]-1-piperidino)-carbonyloxy-camptothecin against pediatric and adult central nervous system tumor xenografts.

Therapy of patients with malignant central nervous system tumors is frequently unsuccessful, reflecting limitations of current surgical, radiotherapeutic, and pharmacotherapeutic treatments. The camptothecin derivative irinotecan (CPT-11) has been shown to possess antitumor activity in phase II trials for patients with carcinoma of the lung, cervix, ovary, colon, or rectum and for patients with non-Hodgkin's lymphoma. The current study was designed to test the efficacy of the drug against a panel of human tumor xenografts derived from adult and pediatric central nervous system malignancies. Tumors included childhood high-grade gliomas (D-212 MG, D-456 MG), adult high-grade gliomas (D-54 MG, D-245 MG), medulloblastomas (D341 Med, D487 Med), ependymomas (D528 EP, D612 EP), and a rhabdomyosarcoma (TE-671), as well as sublines with demonstrated resistance to busulfan (D-456 MG (BR)), cyclophosphamide (TE-671 CR), procarbazine (D-245 MG (PR)) or melphalan (TE-671 MR), growing subcutaneously and intracranially in athymic nude mice. In replicate experiments, CPT-11 was given at a dosage of 40 mg/kg per dose via intraperitoneal injection in 10% dimethylsulfoxide on days 1-5 and 8-12, which is the dosage lethal to 10% of treated animals. CPT-11 produced statistically significant (P < 0.001) growth delays in all subcutaneous xenografts tested, including those resistant to busulfan, cyclophosphamide, procarbazine, and melphalan, with growth delays ranging from 21.3 days in D487 Med to 90+ days in several tumor lines. Further, tumor regression was evident in every treated animal bearing a subcutaneous tumor, with some xenografts yielding complete tumor regression. Statistically significant (P < 0.001) increases in survival were demonstrated in the two intracranial xenografts-D341 EP (73.0% increase) and D-456 MG (114.2% increase)-treated with CPT-11. These studies demonstrate that, of over 40 drugs evaluated in this laboratory, CPT-11 is the most active against central nervous system xenografts and should be advanced to clinical trial as soon as possible.

Busulfan therapy of central nervous system xenografts in athymic mice

We evaluated the antitumor activity of busulfan against a panel of tumor cell lines and xenografts in athymic nude mice derived from childhood high-grade glioma, adult high-grade glioma, ependymoma, and medulloblastoma. Busulfan displayed similar activity against a panel of four medulloblastoma cell lines (D283 Med, Daoy, D341 Med, and D425 Med) and four corresponding sublines with laboratory-generated or clinically acquired resistance to 4-hydroperoxycyclophosphamide [D283 Med (4-HCR), Daoy (4-HCR), D341 Med (4-HCR), and D458 Med] and cross-resistance to melphalan. This is consistent with a nearly total lack of cross-resistance of busulfan to 4-hydroperoxycyclophosphamide. Busulfan was active in the therapy of all but one of the subcutaneous xenografts tested, with growth delays ranging from 14.3 days in D612 EP to 58.4 days in D528 EP. Busulfan produced statistically significant increases in the median survival of mice bearing intracranial D456 MG (66%-90%), D612 EP (18%-33%), and D528 EP (89%) xenografts. These studies suggest that busulfan may be active against medulloblastomas, high-grade gliomas, and ependymomas as well as against cyclophosphamide-resistant neoplasms.

Activity of 9-dimethylaminomethyl-10-hydroxycamptothecin against pediatric and adult central nervous system tumor xenografts

The activity of dimethylaminomethyl-10-hydroxycamptothecin (topotecan) was evaluated against a panel of xenografts derived from ependymomas (D528 EP, D612 EP), childhood high-grade gliomas (D-456 MG, D-212 MG), adult high-grade gliomas (D-245 MG, D-54 MG), and medulloblastomas (D425 Med) growing s.c. and i.c. (intracranially) in athymic nude mice. Topotecan was given at a dose of 1.9 mg/kg by i.p. injection in 0.9% saline using a volume of 90 ml/m2 on days 1-5 and 8-12, which represents the dose lethal to 10% of treated animals. Topotecan was active in the therapy of all s.c. xenografts tested, with growth delays ranging from 6.3 days in D-54 MG to 55.7 days in D528 EP. Topotecan produced statistically significant tumor regressions in D425 Med, D-456 MG, D-245 MG, D528 EP, and D612 EP. No tumor regression was seen in any control animal. Statistically significant increases in median survival were seen in the two i.c. xenografts--D-456 MG (28.6% increase) and D-54 MG (39% increase)--treated with topotecan. These studies suggest that topotecan may be an important new addition to the therapy of central nervous system tumors.