摘要:

Dietary and synthetic isothiocyanates have cancer chemopreventive activity. Dietary isothiocyanates are formed from glucosinolate precursors of ingested green vegetables. Isothiocyanates are absorbed across intestinal cell membranes by passive diffusion and bind reversibly to plasma protein thiols by thiocarbamoylation. Free isothiocyanate enters cells and is converted to the glutathione conjugate by glutathione S-transferases (GSTs). The glutathione conjugate is exported from cells by multidrug resistance proteins (MRPs), and metabolized in the mercapturic acid pathway to the corresponding mercapturic acid. The isothiocyanate is reformed by fragmentation of mercapturic acid pathway metabolites; it is inactivated by slow hydrolysis to the corresponding amine that is inactive in chemoprevention. Depletion of cellular glutathione and protein thiocarbamoylation activates signal transduction for cancer chemoprevention. Isothiocyanates inhibited and inactivated cytochrome P450 isoforms. They induced increased expression of GST, NADPH: quinone oxidoreductase, aldo–keto reductase and&ggr;-glutamylcysteine synthetase. These responses were coordinated at the transcription level by nuclear factor-erythroid 2 p45-related factor-2 acting through the antioxidant/electrophile enhancer response element and stimulated by the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase-1 and c-Jun N-terminal kinase-1 (JNK1) pathway. Isothiocyanates also induced apoptosis of pre-cancerous cells and tumor cells activated by caspase-8 and potentiated by JNK1. The chemopreventive activity of isothiocyanates is influenced by the isothiocyanate bioavailability—as is toxicity, GST polymorphism, protein thiocarbamoylation and probably also by MRP expression. These features of isothiocyanate metabolism and chemoprevention deserve further investigation.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Melphalan was the first described treatment for patients with multiple myeloma in the 1960s and is still being used in clinical practice. However, the use of melphalan in combination with prednisone resulted in a median survival of only 2–3 years. Therefore, the dose of melphalan has been intensified since then (140–200 mg/m2). In order to diminish treatment-related morbidity and mortality due to severe myelosuppression induced by these regimens, high-dose melphalan is currently supported with autologous stem cells. Indications for high-dose therapy and the role of further intensification by performing second or allogeneic transplantations are discussed. Furthermore, new therapeutic modalities, such as inhibitors of angiogenesis, also showing direct antiproliferative, cytokine-related and immunomodulatory effects on plasma cells (thalidomide and its newer deratives), inhibitors of the transcription factor NF-&kgr;B (proteasome inhibitors) and immunotherapy are described.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The presence of DNA fragments circulating in cancer patients was described a number of years ago. The mere presence of DNA in the circulation is not indicative of cancer. However, there are reports that apoptosis and necrosis of the cancer cells can increase the levels of circulating DNA. The study of plasma DNA with the detection of genetic abnormalities associated with specific cancers has produced some promising results. Primary cancer often harborsrasor p53 mutations and the detection of these mutations in free circulating DNA could indicate the presence of cancer. Other approaches have included detection of specific losses of heterozygosity (LOH), microsatellite instability (MI) and promoter hyper-methylation. For breast cancer, studies published to date have focused on detecting LOH, MI and methylation of the p16INK4A promoter. Good concordance between alterations in the primary tumor and detection of the same alterations in the circulation has been observed. Also, it is encouraging to note that DNA alterations have been detected in patients with small or evenin situlesions, indicating that circulating tumor DNA is shed early in the disease process. If ‘universal’ breast-specific DNA alterations can be identified, this approach may hold significant promise for early detection of breast cancer.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Ro 41-4439, a phenyl-pyridine-2-carboxylic acid derivative, was identified by a cell-based screening approach that exploits the differences between normal and cancer cells in their sensitivity to cytotoxic agents. This compound showed low micromolar antiproliferative activity and cytotoxicity against a broad panel of human cancer cell linesin vitro, and over 10-fold selectivity to cancer cells when tested in parallel with a panel of proliferating normal human cells. Cytotoxicity of Ro 41-4439 is due to arrest of cell cycle progression in mitosis followed by induction of apoptosis. Four-week treatment of nude mice bearing established mammary tumor xenografts (MDA-MB-435) with well-tolerated doses of the compound showed 73% inhibition of tumor growth. Limited exploration of structure–activity relationships involving side chain length, and aryl and pyridine rings allowed for the identification of more potent analogs.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Quinones are of significant interest due to their important role in specific cellular functions. Quinoproteins are a big class of oxyreductative agents occurring in bacteria and other organisms. In this investigation derivatives of 2-amino-1,4-benzoquinone, 2-amino-1,4-naphthoquinone and 2-amino-5,8-dihydroxy-1,4-naphthoquinone with a di- and a tripeptide were prepared for first time. The effect of the synthesized compounds on sister chomatid exchange (SCE) rates and human lymphocyte proliferation kinetics on a molar basis was studied. Among these coupled products the most effective in inducing SCEs and depressing proliferation rate indices is the coupling product of 2-amino-1,4-naphthoquinone with the tripeptide GHK (10). Next in order of magnitude in inducing cytogenetic effects is 2-amino-1,4-naphthoquinone (2) and its coupling products with glycine and serine (4 and 5), while the rest displayed marginal activity.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Extracts ofViscum album(mistletoe) are widely used as complementary cancer therapies in Europe. The mistletoe lectins have been identified as the main active principle of mistletoe extracts. They have been shown to exhibit cytotoxic effects as well as immunomodulatory activities. The latter is exemplified by induction of cytokine secretion and increased activity of natural killer cells. Recent reports, however, indicated possible tumor growth stimulation by mistletoe extracts. Therefore, the three aqueous mistletoe extracts (Iscador M special, Iscador Qu special and Iscador P) were evaluated for antiproliferative and/or stimulatory effects in a panel of 16 human tumor cell linesin vitrousing a cellular proliferation assay. The results show no evidence of stimulation of tumor growth by any of the three Iscador preparations, comprising central nervous system, gastric, non-small cell lung, mammary, prostate, renal and uterine cancer cell lines, as well as cell lines from hematological malignancies and melanomas. On the contrary, Iscador preparations containing a high lectin concentration (Iscador M special and Iscador Qu special) showed antitumor activity in the mammary cancer cell line MAXF 401NL at the 15μg/ml dose level with a more than 70% growth inhibition compared to untreated control cells. In addition, a slight antitumor activity (growth inhibition 30–70%) was found in three tumor cell lines for Iscador M special and in seven tumor cell lines for Iscador Qu special, respectively. Iscador P, which contains no mistletoe lectin I, showed no antiproliferative activity.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Ecteinascidin 743 (ET-743) is an anticancer agent derived from the Caribbean tunicateEcteinascidia turbinata. In the present article, the pharmacokinetics and pharmacodynamics of ET-743 are described within a phase I study. Forty patients with solid tumors initially received ET-743 as a 1-h i.v. infusion every 21 days at nine dose levels (50–1100 μg/m2). The maximal tolerated dose (MTD) was 1100 μg/m2, with thrombocytopenia and fatigue as dose-limiting toxicities (DLTs). As this MTD was substantially lower than in parallel phase I studies, dose escalation continued using a prolonged, 3-h infusion. Thirty-two patients were entered at five dose levels (1000–1800 μg/m2). The MTD was 1800 μg/m2with pancytopenia and fatigue as DLTs. The recommended phase II dose was 1650 μg/m2given over 3 h at which 12 patients were treated. Pharmacokinetic monitoring was performed for both treatment schedules. Non-compartmental pharmacokinetic parameters at the recommended dose with the 3-h infusion were (mean value±SD): clearance 87±30 l/h and mean elimination half-life 26±7 h. Pharmacokinetics were linear at the dose range tested with this schedule. The percentage decrease in platelets, white blood cells and neutrophils correlated with the area under the plasma concentration versus time curve (AUC), dose and maximal plasma concentration (Cmax). Hepatic toxicity increased with dose, AUC andCmax. Administration of 1650 μg/m2ET-743 over 3 h seemed clinically feasible; pharmacokinetics were linear with this schedule. Hepatic and hematological toxicities correlated with exposure to ET-743.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Due to concerns about toxicity, many elderly patients with aggressive non-Hodgkin's lymphoma (NHL) are not considered candidates for standard chemotherapy with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP). The cytoprotective agent amifostine has the potential to reduce toxicity when added to chemotherapy. The purpose of the current study was to examine the toxicity of CHOP combined with amifostine in elderly patients with aggressive NHL. A prospective phase II study was performed in patients aged 60 years and older. Patients with stage I/II disease received 4 cycles of CHOP followed by involved-field irradiation. Patients with stage III/IV received 6–8 cycles of CHOP. Amifostine (740 mg/m2) was administered as a 15-min i.v. infusion immediately before chemotherapy. Forty-one (median age 69.5 years, range 60–87) of 49 consecutive previously untreated patients, aged 60 years and older, with aggressive NHL seen in our center were included in the study. Twenty-one patients had stage I/II disease and 20 had stage III/IV disease. The patients received a total of 207 cycles of amifostine–CHOP. Infusion of amifostine caused mild to moderate transient side effects, including a drop of systolic blood pressure >20 mmHg in 54 cycles and nausea/vomiting in 36 cycles. Hematotoxicity of CHOP consisted of leukopenia grade 4 in only 15.4% of cycles. There were two cases of grade 3 anemia. No thrombocytopenia higher than grade 2 occurred. Febrile neutropenia was rare, occurring in 4.3% of cycles. One patient died after the first CHOP administration because of anthracycline-related acute cardiomyopathy (corresponding to a toxic death rate of 2.4%). The complete response rates were 85 and 75% in stage I/II and stage III/IV patients, respectively. After median follow-up of 33 months (range 17–50 months) the median overall survival was not reached in patients with stage I/II and was found to be 32 months in patients with stage III/IV. At 2 years, 76% of patients with stage I/II and 70% with stage III/IV were alive. Twelve of the 15 patients who died were aged older than 70. Amifostine pre-treatment was associated with a low toxicity of CHOP in elderly patients with aggressive NHL treated with curative intent. Treatment outcomes appeared not to be impaired by the addition of amifostine to CHOP. This schedule merits further testing in a randomized trial.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Capecitabine, a tumor-selective, oral fluoropyrimidine, has demonstrated significant antitumor activity in patients with metastatic breast cancer. In this open-label monocenter phase II study the efficacy and safety of capecitabine in patients with metastatic breast cancer who relapsed after high-dose chemotherapy was examined. Female patients 18-65 years of age, with a histologically confirmed diagnosis of metastatic breast cancer, who relapsed after high-dose chemotherapy (adjuvant and/or metastatic) followed by autologous peripheral blood stem cell transplantation (PBSCT) and who had been treated in their course of the disease with an anthracycline and/or an anthracycline/taxane containing regimen were included into this clinical study. Capecitabine was applied as the first salvage chemotherapy at relapse after high-dose chemotherapy (1250 mg/m2b.i.d. p.o. for 14 days followed by 7 days rest period). Responding patients or those with stable disease after two treatment cycles were offered to continue treatment until tumor progression. Response rate, time to disease progression, survival, toxicity and quality of life were assessed. Fourteen patients between 35 and 60 years (median 45.5 years) entered this study and received a median number of 5 cycles (range 1–19) of capecitabine. All patients were evaluable for response. All patients had been pretreated with 1–2 cycles of high-dose chemotherapy plus PBSCT. Furthermore, 13 patients had additionally received local radiotherapy. On average, the patients showed metastatic disease in two organ sites (range 1–4 sites). One patient obtained a complete response and five patients a partial response, accounting for a response rate of 42.9% [95% confidence interval (17.7%; 71.1%)]. All responses were already achieved at the first observation time point 6 weeks after treatment initiation. Two further patients obtained stable disease for at least 12 weeks. At the time of final analysis all patients have progressed. Median time to progression was 2.8 months (range 0.4–13.3 months). No median survival time was reached (range 3.9–36.5 months, at the time of reporting eight patients were alive and six patients had died). Two patients developed grade III granulocytopenia. Five patients developed grade III hand–foot syndrome. One patient had the combination of nausea, fever and diarrhea grade III. All adverse events were considered manageable. We conclude that capecitabine as single-agent oral chemotherapy is active and well tolerated in heavily pretreated patients with breast cancer. It can be safely used in patients who have been intensively pretreated by myelotoxic chemotherapy or who have even relapsed after high-dose chemotherapy with PBSCT.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Dihydropyrimidine dehydrogenase (DPD) and dihydropyrimidinase (DHP) are metabolic enzymes of fluoropyrimidine. UFT containing uracil (U) and Tegafur is the first reported DPD-inhibitory fluoropyrimidine. To clarify the significance of the enzyme activities, we examined the relationships between the effects and adverse reactions, and DPD and DHP activities in gastric cancer treated with UFT1+cisplatin neoadjuvant chemotherapy. Twenty-five gastric cancer patients were administered UFT at 370 mg/m2/day for 21 days and cisplatin at 15 mg/m2/day for 2 days. Dihydrouracil (DU) and U levels in the urine and DPD activities in the resected tumors were measured. Chemotherapeutic effects were classified histologically into non-responder and responder groups. The responder group accounted for 48% of the patients. All six patients with high DPD activities (≥0.08 nmol/min/ww) belonged to the non-responder group and 11 of 19 patients with low DPD activities (<0.08 nmol/min/ww) belonged to the responder group; the difference was significant (p=0.0435). Adverse reactions to UFT occurred in four patients, all of whom were among the six patients with abnormal DU/U values. The incidence of UFT adverse reactions was estimated at 67%. In conclusion, the measured levels of DPD-related enzyme activities appear to be significant for predicting the effects and adverse reactions to chemotherapy.

ISSN:0959-4973    

出版商:OVID    

年代:2002

数据来源: OVID