Purpose: The hallmark of neurofibromatosis type 2 (NF2) is bilateral vestibular schwannomas (VS). Approximately 80% of NF2 patients also have intracranial meningiomas. Vascular endothelial growth factor (VEGF) is expressed in both NF2-related and sporadic occurring meningiomas and anti-VEGF therapy (bevacizumab) may, therefore, be beneficial in NF2-related meningiomas.
View Article and Find Full Text PDFThe hallmark of neurofibromatosis type 2 (NF2) is bilateral vestibular schwannomas (VS) and severe hearing loss is common in NF2 patients. Vascular endothelial growth factor (VEGF) expression level in NF2 correlates with tumour growth rate and bevacizumab, a VEGF-binding antibody, has previously been shown to induce tumour shrinkage and improve hearing. We retrospectively reviewed the effect of bevacizumab on hearing and VS tumour size in 12 consecutive NF2 patients.
View Article and Find Full Text PDFThe bisdioxopiperazines such as (+)-(S)-4,4'-propylenedi-2,6-piperazinedione (dexrazoxane; ICRF-187), 1,2-bis(3,5-dioxopiperazin-1-yl)ethane (ICRF-154), and 4,4'-(1,2-dimethyl-1,2-ethanediyl)bis-2,6-piperazinedione (ICRF-193) are agents that inhibit eukaryotic topoisomerase II, whereas their ring-opened hydrolysis products are strong iron chelator. The clinically approved analog ICRF-187 is a pharmacological modulator of topoisomerase II poisons such as etoposide in preclinical animal models. ICRF-187 is also used to protect against anthracycline-induced cardiomyopathy and has recently been approved as an antidote for alleviating tissue damage and necrosis after accidental anthracycline extravasation.
View Article and Find Full Text PDFIn a number of cancer types high tumor tissue levels of plasminogen activator inhibitor type 1 (PAI-1) protein are strongly associated with shorter cancer patient survival. This association has been intriguing since PAI-1 is known to inhibit urokinase plasminogen activator (uPA) that converts plasminogen to plasmin, which is actively involved in tumor progression and invasion. In order to further explore the biological role of PAI-1 in cancer, we have prepared fibroblasts from PAI-1 gene deficient mice and from their wild type littermates.
View Article and Find Full Text PDFPurpose: The treatment of patients with brain metastases is presently ineffective, but cerebral chemoradiotherapy using radiosensitizing agents seems promising. Etoposide targets topoisomerase II, resulting in lethal DNA breaks; such lesions may increase the effect of irradiation, which also depends on DNA damage. Coadministration of the topoisomerase II catalytic inhibitor dexrazoxane in mice allows for more than 3-fold higher dosing of etoposide.
View Article and Find Full Text PDFPurpose: The anthracyclines daunorubicin and doxorubicin and the epipodophyllotoxin etoposide are potent DNA cleavage-enhancing drugs that are widely used in clinical oncology; however, myelosuppression and cardiac toxicity limit their use. Dexrazoxane (ICRF-187) is recommended for protection against anthracycline-induced cardiotoxicity.
Experimental Design: Because of their widespread use, the hematologic toxicity following coadministration of dexrazoxane and these three structurally different DNA cleavage enhancers was investigated: Sensitivity of human and murine blood progenitor cells to etoposide, daunorubicin, and doxorubicin +/- dexrazoxane was determined in granulocyte-macrophage colony forming assays.
Purpose: The pharmacokinetics of etoposide were studied in cancer patients with brain metastases treated with high-dose etoposide in order to determine if the pharmacokinetics were altered by the use of dexrazoxane as a rescue agent to reduce the extracerebral toxicity of etoposide.
Methods: Etoposide plasma levels were determined by HPLC.
Results: The etoposide pharmacokinetics described by a monophasic first-order elimination model were found to be similar to other reported data in other settings and at similar doses.
Purpose: The study was undertaken to determine the metabolism of dexrazoxane (ICRF-187) to its one-ring open hydrolysis products and its two-rings opened metal-chelating product ADR-925 in cancer patients with brain metastases treated with high-dose etoposide. In this phase I/II trial dexrazoxane was used as a rescue agent to reduce the extracerebral toxicity of etoposide.
Methods: Dexrazoxane and its one-ring open hydrolysis products were determined by HPLC and ADR-925 was determined by a fluorescence flow injection assay.