Enhanced therapeutic efficacy of 5'deoxy-5-fluorouridine in 5-fluorouracil resistant head and neck tumours in relation to 5-fluorouracil metabolising enzymes.

Four human head and neck xenograft (HNX) tumour lines grown in nude mice and two murine colon carcinomas (Colon 26 and 38) were tested for their sensitivity to 5-fluorouracil (5-FU) and its prodrug 5'deoxy-5-fluorouridine (Doxifluridine, 5'd-FUR). 5-FU sensitivity at the maximum tolerated dose (MTD) showed the following pattern; HNX-DU less than HNX-KE = HNX-E = HNX-G less than Colon 26 much less than Colon 38. The sensitivity pattern to 5'd-FUR was: HNX-DU less than HNX-G less than HNX-E less than HNX-KE less than Colon 38 less than Colon 26.

Immunohistochemical detection of P-glycoprotein in human tumor cells with a low degree of drug resistance.

We report the immunohistochemical detection of the 170-180 kDa multi-drug-resistance-related P-glycoprotein in human tumor cells with a low level of resistance. A series of human squamous lung cancer cell lines with increasing levels of resistance to doxorubicin (DOX) was developed and stained for P-glycoprotein, using the JSB-IMAb. Subline SW1573/50A with a 4- to 6-fold cross-resistance to daunorubicin (DNR) and vincristine (VCR) showed rather uniform positive staining for P-glycoprotein apparently at cytoplasmic sites.

Immunohistochemical detection and quantitation of P-glycoprotein in multiple drug-resistant human myeloma cells: association with level of drug resistance and drug accumulation.

Using several multiple drug-resistant human myeloma cell lines as standards, we developed an immunohistochemical staining technique and means of quantitating P-glycoprotein in individual myeloma cells. The level of staining intensity for P-glycoprotein in individual myeloma cells was quantitated by measuring the average optical density of each cell with a microscopic computerized cell analysis system. Using this system, we observed that the level of P-glycoprotein for individual cells within a cell population of known drug sensitivity was very homogeneous (coefficient of variation less than or equal to 13%).

Palliative care for brain metastases of solid tumour types.

Prognostic factors for survival were analyzed retrospectively in 214 patients with brain metastases of the solid tumour type. The most frequent neurological signs and symptoms at diagnosis of cerebral involvement were headache-nausea-vomiting and focal weakness. Similar numbers of patients were found to have solitary metastasis and multiple lesions.

Reversal of 5-fluorouracil-induced myelosuppression by prolonged administration of high-dose uridine.

The effect of high-dose uridine on 5-fluorouracil (5-FU)-induced toxicity was investigated. Nine patients were treated weekly with 5-FU at increasing dosages. Five patients developed dose-limiting leukopenia, and four patients developed thrombocytopenia.

Mucocutaneous side effects of Brequinar sodium. A new inhibitor of pyrimidine de novo biosynthesis.

Brequinar sodium (NSC 368390; DUP 785) is a new inhibitor of pyrimidine de novo biosynthesis which has completed Phase I clinical trials within the framework of the Early Clinical Trials Group of the European Organization for Research and Treatment of Cancer (EORTC). The main side effects of this compound are myelosuppression, nausea and vomiting, stomatitis and/or mucositis, and skin rash. In this report, the authors describe the pattern of mucocutaneous side effects of Brequinar sodium in patients who received the drug by four different schedules: (1) short-term intravenous (IV) infusion every 3 weeks; (2) weekly; (3) twice weekly; and (4) five times daily every 4 weeks.

Lack of effectiveness of combined 5-fluorouracil and leucovorin in patients with 5-fluorouracil-resistant advanced colorectal cancer.

Favorable results have been reported for the treatment of advanced colorectal cancer with the combination of 5-fluorouracil (5-FU) and leucovorin (LV). In these investigations the highest response rates were obtained in non-pretreated patients. In the present study, 22 patients with primary or acquired resistance to single-agent 5-FU and documented progressive disease on 5-FU were given a bolus injection of LV at a dose of 200 mg/m2, 1 h prior to a 2 h infusion of 5-FU at a dose of 370-770 mg/m2 on 5 consecutive days, and this was repeated every 3 weeks.

Mechanism of action of antitumor drug etoposide: a review.

Metabolism studies of the antitumor drug etoposide show the formation of metabolites in the lactone ring, which are probably not important for the drug's mechanism of action, and oxidative transformations in the dimethoxyphenol ring (E ring), which lead to products that can cause DNA damage and may play a role in the drug's mechanism of action. The cytotoxicity of etoposide is caused by the induction of DNA damage. The occurrence of the DNA lesions can be explained by the capacity of the drug to interfere with the scission-reunion reaction of mammalian topoisomerase II by stabilizing a cleavable complex.

Pharmacokinetics of 5-fluorouracil assessed with a sensitive mass spectrometric method in patients on a dose escalation schedule.

The pharmacokinetics of 5-fluorouracil (5-FUra) was investigated in 21 patients with advanced cancer (mainly colorectal cancer). 5-FUra was administered as weekly i.v.

Combined radiation therapy and daily low-dose cisplatin for inoperable, locally advanced non-small cell lung cancer: results of a phase II trial.

The Free University Hospital in Amsterdam conducted a phase II trial on inoperable patients with non-small cell lung cancer (NSCLC) to evaluate the role of cisplatin as a radiosensitizer. Forty patients were entered into the study. Thirty-three patients were evaluable for response and 37 for toxicity.

A sensitive non-radioactive assay for pyrimidine nucleoside phosphorylase using reversed-phase high performance liquid chromatography.

A new sensitive assay for pyrimidine nucleoside phosphorylase using non-radioactive substrates is described. With the natural substrate uridine (UR) and the analog, 5'-deoxy-5-fluorouridine (5'dFUR) conditions have been optimized to measure the product formation with reversed-phase high-performance liquid chromatography. Using automated injection large series of samples may be analyzed.

Morphometric study of myocardial changes during doxorubicin-induced cardiomyopathy in mice.

Doxorubicin (DOX) is one of the most effective anti-cancer drugs in oncology, but may cause a cumulative dose-dependent cardiomyopathy in a number of cancer patients. The effect of DOX on the heart was studied in mice treated with i.v.

Fluorouracil: biochemistry and pharmacology.

Fluorouracil (5FU) is still considered the most active antineoplastic agent in the treatment of advanced colorectal cancer. The drug needs to be converted to the nucleotide level in order to exert its effect. It can be incorporated into RNA leading to interference with the maturation of nuclear RNA.

Effects of the ortho-quinone and catechol of the antitumor drug VP-16-213 on the biological activity of single-stranded and double-stranded phi X174 DNA.

We have studied the effects of the recently reported two new metabolites of the antitumor agent VP-16-213, the ortho-dihydroxy derivative or catechol and the ortho-quinone, on the biological activity of single-stranded and double-stranded phi X174 DNA, the binding of the metabolites to calf thymus DNA and the conversion of the catechol into the ortho-quinone. Evidence was obtained for the oxidation of the catechol into the ortho-quinone and for the fact that the ortho-quinone is the metabolite of VP-16-213 responsible for its binding to rat liver microsomal proteins. The catechol and ortho-quinone of VP-16-213 were found to bind 7-9 times more strongly to calf thymus DNA than VP-16-213 itself.

Structure-bioactivation relationship of a series of podophyllotoxin derivatives.

With the aim of elucidating the structural requirements for O-demethylation of the antitumor agent VP-16-213 by cytochrome P-450, the binding of a series of podophyllotoxin derivatives to rat liver microsomal cytochrome P-450 was studied. The examined podophyllotoxin derivatives were: VP-16-213, VM-26, podophyllotoxin, 4'-demethylepipodophyllotoxin (the aglycone of VP-16-213 and VM-26) and 3,5-dimethoxy-4-hydroxytoluene (a model compound for the E-ring of VP-16-213). The binding to phenobarbital (Pb)-induced microsomes was more extensive than that to 3-methylcholanthrene (3-MC)-induced microsomes.

Phase II trial of menogaril in advanced colorectal cancer.

Menogaril, a new semisynthetic anthracycline antibiotic, was administered to 35 patients with advanced colorectal cancer. The drug was infused over 2 hr at a dose of 160 mg/sqm or 200 mg/sqm repeated every 4 weeks. Twenty-seven patients were evaluable for response and no objective responses were achieved.

DUP 785 (NSC 368390): schedule-dependency of growth-inhibitory and antipyrimidine effects.

DUP 785 (NSC 368390; Brequinar sodium) is a new inhibitor of pyrimidine de novo biosynthesis with antitumor activity against several experimental tumors. DUP 785 inhibits the mitochondrial enzyme dihydroorotate dehydrogenase, blocking the conversion of dihydroorotate to orotate. We examined the influence of exposure time to DUP 785 on its growth-inhibitory effects in L1210 murine leukemia and WiDR human adenocarcinoma cells and the effects of pyrimidine (deoxy) nucleosides on reversal of growth-inhibition.