Nonenzymatic and glutathione S-transferase (GST) catalyzed glutathione (GSH) conjugation has been postulated as a mechanism by which alkylating cytostatic drugs can be inactivated intracellularly. In this study, we describe studies on the glutathione-dependent biotransformation of thiotepa (tris(1-aziridinyl)phosphine sulfide), a trifunctional alkylating agent. 31P NMR studies showed that thiot...

Because the transport and accumulation of thiotepa by cells has not been characterized, these process were investigated with [14C]thiotepa and cultured L1210 or freshly obtained human or avian RBC. The octanol:phosphate buffered saline partition coefficient of thiotepa was 2.4 +/- 0.1 (n = 8). With this value, the permeability coefficient (P) for thiotepa was estimated to be between 2.8 X 10(-4...

Thiotepa is a bifunctional alkylating anticancer drug that is a rodent carcinogen and a suspected human carcinogen. In order to determine the sensitivity of mutant induction in the Hprt lymphocyte assay for detecting tumorigenic doses of thiotepa, Fischer 344 rats were treated for 4 weeks with thiotepa using a procedure adapted from a carcinogenesis protocol. At various times after beginning th...

Cytochrome P450 2B6 is a genetically polymorphic enzyme that is important in the metabolism of a number of clinically used drugs. This enzyme is not as well studied as other cytochrome P450 (P450) isoforms because of the lack of specific antibodies, probe drugs, and inhibitors. Although recent progress has been made toward specific antibodies and probe drugs, a specific enzyme inhibitor is stil...

BACKGROUND Exposure to the chemotherapeutic alkylating agent thiotepa during brain development leads to neurological complications arising from neurodegeneration and irreversible damage to the developing central nerve system (CNS). Administration of single dose of thiotepa in 7-d postnatal (P7) rat triggers activation of apoptotic cascade and widespread neuronal death. The present study was aim...

AIM To investigate the effects of single, short-term (5 or 30 minutes) exposures to thiotepa or 5-fluorouracil (5-FU) on collagen lattice contraction and retinal pigment epithelial (RPE) cell proliferation. METHODS For collagen contraction studies, RPE cells seeded into free floating type I collagen lattices were exposed to single 5 or 30 minute treatments with thiotepa (0.06-4 mg/ml), or 5-F...

Our purpose was to determine the feasibility of a regimen of multiple, rapidly cycled courses of high-dose alkylating agents, including paired courses of escalating doses of thiotepa, supported by peripheral blood progenitor cells and filgrastim, in patients with responding stage IV breast cancer. The regimen consisted of two courses of cyclophosphamide (3.0 g/m2/course) followed by two courses...

Pentoxifylline potentiates the cytotoxicity of alkylating agents in preclinical models. In this study we sought to define the maximum tolerated dose (MTD) of N,N',N"-triethylenethiophosphoramide (thioTEPA) with pentoxifylline, and to estimate the antitumor response to this combination in previously treated breast cancer patients. Thirty-five previously treated advanced breast cancer patients re...

Introduction. Osteosarcoma relapse has a poor prognosis, with less than 25% survival at 5 years. We describe the experience of the French Society of Paediatric Oncology (SFCE) with high dose (HD) thiotepa and autologous stem cell transplantation (ASCT) in 45 children with relapsed osteosarcoma. Patients and Methods. Between 1992 and 2004, 53 patients received HD thiotepa (900 mg/m(2)) followed ...

N,N',N''-Triethylenethiophosphoramide ([14C]thiotepa) accumulation by L1210 cells is a biphasic process. A very rapid initial phase is followed by a much slower second phase that reflects accumulation of radioactivity in a form that is not lost or exchanged when cells are resuspended and incubated in drug-free medium for up to 8 h. In this study we attempted to characterize this nonexchangeable...