Effect of the aromatase inhibitor vorozole on estrogen and progesterone receptor content of rat mammary carcinomas induced by 1-methyl-1-nitrosourea

Vorozole, a nonsteroidal aromatase inhibitor, impedes the post-initiation stage of chemically induced mammary carcinogenesis. While various aspects of vorozole's effects on mammary carcinoma development have been investigated, little attention has been directed to determining the estrogen receptor (ER) and progesterone receptor (PR) content of mammary carcinomas that arise despite vorozole treatment. Female Sprague–Dawley rats were given an i.p. injection of 50mg MNU/kg body weight at 21 days of age and placed on diet supplemented with 0 or 3mg vorozole/kg, which had no effect on mammary tumor development. Histologically confirmed carcinomas were evaluated for ER and PR by immunohistochemistry. In the control group, 78.8% of carcinomas were ER positive with an ER content ranging from 13.8 to 40.0%, similar to ER content of mammary ductal epithelial cells from non-carcinogen treated animals. PR content ranged from 4.4 to 45.2% and also was similar to levels of PR observed in ductal epithelial cells. ER was not correlated with PR in mammary carcinomas (r=0.05, p>0.80), whereas there was a significant correlation in ductal epithelium (r=0.86, p=0.006). In vorozole-treated rats, no ER negative carcinomas were observed and overall ER expression by vorozole was elevated (p<0.03). All carcinomas from vorozole-treated rats expressed PR (2.5–60.2%) and correlation between ER and PR content was numerically greater in carcinomas from vorozole-treated animals (r=0.42, p=0.09). These data, which are considered hypothesis generating, provide evidence that low doses of vorozole in the diet select for mammary carcinomas with an increased ER positive phenotype.     

Tumour necrosis factor‐α and interleukin‐1 and ‐6 in fibrocystic breast disease

The risk of developing breast cancer is higher in women presenting gross cystic disease (cysts > 3mm in diameter) of the breast with intracystic K+/Na+ > 3 as compared with K+/Na+ < 3. The present study reports the levels of tumour necrosis factor (TNF), interleukin1 (IL1), and interleukin6 (IL6) in the breast cyst fluid of women with gross cystic disease and analyses the relationship between the intracystic concentration of these cytokines, sex steroid hormones, and the K+/Na+ ratio. The concentration of these cytokines, estradiol, testosterone, dehydroepiandrosterone sulfate (DHEAS), and 17OHprogesterone were determined in the breast cyst fluid of 54 women with gross cystic disease. No significant differences were found in the cystic levels of IL1 between cysts with intracystic K+/Na+ < 3 and > 3. However, in cysts with intracystic K+/Na+ > 3 we found a lower concentration of IL6 and TNF than in those with intracystic K+/Na+ < 3.Stepwise multiple linear regression analysis demonstrated that the concentration of IL6 in breast cyst fluid was predicted statistically by a negative regression coefficient for the concentration of estradiol and DHEAS, and by a positive regression coefficient for the concentration of TNF. The concentration of TNF in breast cyst fluid was predicted statistically by a positive regression coefficient for the concentration of IL6, and by a negative regression coefficient for the concentration of estradiol. No candidate variable was included in the model to predict concentrations of IL1 in breast cyst fluid. Our results indicate that IL6 and TNF could have a local protector role in gross cystic disease, and that they could be used as a marker to identify cyst type.     

Induction of insulin‐like growth factor binding protein expression by ICI 182,780 in a tamoxifen‐resistant human breast cancer cell line

Earlier studies in our laboratory demonstrated that the steroidal antiestrogen ICI 182,780 is very effective in abolishing the tamoxifenresistant proliferation of MCF 7/523 cells [1]. In addition, preliminary binding studies showed that ICI 182,780 increased the binding of insulinlike growth factor (IGF)I to the MCF 7/523 cells, although this finding was not the result of an increase in the expression of the insulinlike growth factorI receptor (IGFIR). Hence, we reasoned that the inhibition of tamoxifenresistant cell growth by ICI 182,780 might have been due to increased expression of insulinlike growth factor binding proteins (IGFBPs).We observed the upregulation of noninsulinsuppressible IGFI binding in both the tamoxifensensitive MCF 7/521 cell line (1.5fold) and the tamoxifenresistant MCF 7/523 cell line (2.5fold) after 5 days of treatment with ICI 182,780 (10^–7 M) in serumfree medium, suggesting a role for cellassociated IGFBPs. Affinity crosslinking experiments confirmed the presence of an IGFI:IGFBP complex of approximately 38kDa in tamoxifen or ICI 182,780treated cells. Western ligand blots showed higher levels of a soluble 30kDa IGFBP in media conditioned by either of the subclones that had been treated with ICI 182,780, an effect consistently opposed by estrogen (E₂:10^–9 M). RTPCR showed higher levels of IGFBP5 mRNA than any of the other known IGFBPs, suggesting that this was the major IGFBP subtype. The protein was subsequently identified by Western immunoblotting as IGFBP5. In conclusion, we postulate that this may be a mechanism contributing to the greater potency of ICI 182,780 in the growth inhibition of the MCF 7/523, tamoxifenresistant cell line.     

Irofulven Induces Apoptosis in Breast Cancer Cells Regardless of Caspase-3 Status*

Caspase-3 deficiency can limit the efficiency of pro-apoptotic anticancer treatments. Irofulven (hydroxymethylacylfulvene, HMAF, MGI 114, NSC 683863) is an antitumor drug, currently in a Phase III and multiple Phase II trials, which can differentiate between tumor and normal cells in apoptosis induction. This study investigated whether apoptosis induced by irofulven requires caspase-3. Irofulven action was compared in breast cancer cells differing in caspase-3 status: deficient MCF-7 cells and proficient MDA-MB-231 cells and in normal human mammary epithelial cells, HMEC. Irofulven induces significant, concentration and time-dependent apoptotic DNA fragmentation in breast cancer cell lines, regardless of caspase-3 status. After 12, 24 and 48h incubation at 1M irofulven ( 3×GI₅₀), fragmented DNA comprised 3.7, 14.1 and 34.6% and 8.4, 12.6 and 20.3% of total DNA in MCF-7 and MDA-MB-231 cells, respectively. Cell viability (trypan blue exclusion) remained largely unaffected during the first 24h but decreased markedly after 48h, indicating secondary necrosis. Net losses in cell numbers were apparent at 48h. Normal HMEC cells were refractory to 1M drug with only 3–9% fragmented DNA after 12–48h, although apoptosis was observed at drug levels >3M. The broad-spectrum caspase inhibitor Z-VAD-fmk inhibited irofulven-induced apoptosis of all cell lines at 20M with nearly complete abrogation of apoptosis at 100M. Irofulven treatment resulted in marginal caspase-3 processing in MDA-MB-231 and HMEC cells. These results indicate that whereas the caspase cascade mediates irofulven- induced apoptosis, caspase-3 is dispensable (supported by NIH CA70091 and CA78706).     

1-β-d-arabinofuranosylcytosine-, mitoxantrone-, and paclitaxel-induced apoptosis in HL-60 cells: improved method for detection of internucleosomal DNA fragmentation

We investigated the ability of different doses and durations of exposure to the chemotherapeutic drugs 1--d-arabinofuranosylcytosine (Ara-C), mitoxantrone (MTN), and paclitaxel (taxol, TXL) to induce internucleosomal DNA fragmentation and apoptosis in human acute myeloid leukemia (AML) HL-60 cells in suspension culture. At clinically achievable concentrations, all three drugs have been shown to induced apoptosis in HL-60 cells. An improved method was developed for the isolation of pure genomic DNA and the detection of drug-induced intergenomic DNA and the detection of drug-induced internucleosomal DNA fragmentation in <1.0 g of DNA sample by agarose gel electrophoresis. Morphologic evidence for apoptosis was determined by light microscopy following Wright staining, and cell viability was assessed by trypan blue dye exclusion. Internucleosomal DNA fragmentation was observed following exposure to 1.0 M Ara-C for 4 h, which increased with 10 and 50 M Ara-C. Incubation with 100 M Ara-C produced internucleosomal DNA fragmentation starting at 3 h, which increased with longer periods of exposure to Ara-C. Utilizing a schedule of 1-h exposure followed by 3-h suspension in drug-free medium, 0.25 M MTN was found to initiate DNA fragmentation, which increased with exposure to 1.0 and 5.0 M MTN. However, identical treatment with higher concentrations of MTN resulted in random DNA degradation. Alternatively, continuous exposure to 1.0 M MTN for 3 h was necessary to initiate internucleosomal DNA fragmentation. This increased with exposure intervals of up to 6 h. Exposure to TXL concentrations as low as 0.01 M for 24 h caused internucleosomal DNA fragmentation, which increased with dose escalation (0.05, 0.1, 0.5, and 1.0 M) of TXL. Although continuous exposure to 1.0 M TXL for a period as short as 8 h produced internucleosomal DNA fragmentation, this increased significantly with longer exposure intervals. In general there appears to be a threshold concentration and duration of exposure below which non of these three drugs activates endonucleolytic internucleosomal DNA fragmentation and apoptosis. This threshold is lower for the DNA-interactive drugs MTN and Ara-C but higher for the non-DNA-interactive drug TXL. Higher doses or prolonged treatments with the drugs produce random DNA fragmentation associated with necrotic cell death. These in vitro results may further improve our understanding of the antileukemic cytotoxic effects of these drugs, which may enable a more rational design of drug regimens for optimal treatment of AML.     

Prognostic significance of preoperative MRI scans in glioblastoma multiforme

Tumor necrosis, enhancement, and associated edema in patients with glioblastoma multiforme (GBM) represent biological variables that can be quantitated on preoperative MRI scans. We reviewed 48 highly selected patients, all of whom had supratentorial lesions, had undergone gross total tumor resection, and had received adjuvant treatments (radio- and chemotherapies). None of these patients had had surgery for recurrent tumor resection and none had harbored multifocal tumors. The median age was 50 years. The median Karnofsky performance score was 80. Multivariate analysis using the Cox regression model revealed that the strongest prognostic variable was the amount of tumor necrosis on preoperative scan (P < 0.001), with median survivals of 42, 24, 15, and 12 months for tumor necrosis grades of 0 (7 pts), I (11 pts),11 (9 pts), and III (21 pts), respectively. The intensity of enhancement of the tumor nodule was another prognostic factor (P = 0.003), with median survivals of 35, 18, and 13.5 months for enhancement grades of 0 (2 pts), I (22 pts), and II (24 pts), respectively. The extent of peritumoral edema had a quadratic effect (P = 0.001), with grades I (19 pts), II (22 pts), and III (7 pts) surviving for 24,12, and 20 months respectively. Location and volume of tumors were not statistically significant predictors of survival (P < 0.05). In conclusion, in this highly selected group, GBM patients with little or no necrosis and with less tumor nodule enhancement on preoperative MRI survive longer than patients with greater amounts of necrosis and greater degrees of tumor enhancement. In addition, a moderate degree of peritumoral edema is associated with worse prognosis.     

Valeur pronostique des mesures de qualité de vie en cancérologie

Résumé: En cancérologie, de nombreuses études ont souligné la valeur pronostique de données issues dévaluations de la qualité de vie (QdV). Lévaluation de la QdV est une mesure des perceptions du patient de limpact de la maladie et des traitements sur son bien-être. Des facteurs pronostiques sont identifiés en relation avec la survie, la réponse au traitement ou la morbidité. La mise en évidence de la valeur pronostique de données de qualité de vie a surtout été effectuée en maladie métastatique; sa valeur se révèle parfois supérieure à celle dindices pronostiques évalués par le clinicien comme lindice de Karnofsky ou létat général OMS. Pour les cancers du sein localisés, les résultats détudes sont hétérogènes. Lexplication la plus plausible du lien entre données de QdV et durée de survie serait que les données de QdV reflètent une perception précoce par le patient de signes subtils de progression de la maladie non relevés par les variables moins nuancées de linterrogatoire médical. Une autre explication porte sur linfluence de processus psychologiques comme loptimisme, lespoir ou un esprit combatif; celle-ci mettrait laccent sur limportance dinterventions psychothérapeutiques favorisant ces dispositions psychologiques pour la survie des patients.Dossier: «Évaluation de la qualité de vie»     

High-dose chemotherapy with autologous stem cell rescue for children with high risk and recurrent medulloblastoma and supratentorial primitive neuroectodermal tumors

Current treatment for high risk and recurrent medulloblastoma (MB) and supratentorial primitive neuroectodermal tumors (stPNET) has a very poor prognosis in children. High dose chemotherapy (HDCT) and autologous stem cell rescue have improved survival rates. We present 19 patients (thirteen classified in the high risk group and six patients with recurrent disease) that received HDCT and autologous stem cell rescue.In the high risk group [Med Pediatr Oncol 38 (2002) 83], all patients underwent neurosurgical debulking. Standard chemotherapy was prescribed in 10 patients. Radiotherapy was given to 4 patients (all older than 4years old). In the recurrence disease group [Childs Nerv Syst 15 (1999) 498], five patients underwent surgery. Radiotherapy was given to those who were not previously irradiated. The HDCT in twelve patients consisted of busulfan 4mg/kg/day, orally over 4days in 6-hourly divided doses and melphalan at a dose of 140mg/m²/day by intravenous infusion over 5min on day –1. Three patients additionally received thiotepa 250mg/m²/day intravenously over 2days and four patients additionally received topotecan 2mg/m²/day over 5days by intravenous infusion over 30min. The other seven patients received busulfan and thiotepa at the same doses.Patients stem cells were mobilized with granulocyte colony-stimulating factor at a dose of 12g/kg twice daily subcutaneously for four consecutive days. Cryopreserved peripheral blood progenitor cells were re-infused 48h after completion of chemotherapy. With a median follow-up of 34months (range 5–93) eight complete responses and one partial response were observed. Three patients died of treatment-related toxicities (15%). The 2 year event-free survival was 37.67±14% in all patients and 57±15% for the high risk group.Therefore we conclude that HDCT may improve survival rates in patients with high risk/recurrent MB and stPNET despite treatment toxicity.     

Pharmacokinetic and pharmacodynamic comparison of fluoropyrimidine derivatives, capecitabine and 5′-deoxy-5-fluorouridine (5′-DFUR)

Purpose Capecitabine is a three-step prodrug that was rationally designed to be a more effective and safer alternative to its intermediate metabolite, 5-deoxy-5-fluorouridine (5-DFUR). We compared the pharmacokinetics/pharmacodynamics of these drugs in metastatic breast cancer patients.Methods Six patients received oral capecitabine at 1657 mg/m² twice daily and 17 received 5-DFUR at 400 mg three times daily. Both drugs were administered for 21 days followed by a 7-day rest.Results Median daily 5-DFUR AUC was significantly higher for capecitabine than for 5-DFUR (81.1 vs 32.6 mmol h/l; P=0.01). Following treatment with 5-DFUR, the median AUC and C_max of 5-DFUR tended to be higher in patients with a partial response (3.83 g h/ml and 4.88 g/ml) and stable disease (6.46 g h/ml and 4.96 g/ml) than in those with disease progression (2.53 g h/ml and 1.36 g/ml). The AUC and C_max of 5-DFUR was significantly related to overall survival.Conclusions These results support the superiority of capecitabine over 5-DFUR.     

Involvement of nuclear steroid/thyroid/retinoid receptors and of protein kinases in the regulation of growth and of c‐erbB and retinoic acid receptor expression in MCF‐7 breast cancer cells

Nuclear steroid/thyroid/retinoid receptors and cerbB membrane receptor tyrosine kinases control epithelial growth and differentiation. Retinoid receptors can dimerize with the vitamin D receptor, the glucocorticoid receptor or the thyroid receptor. Furthermore, multiple cerbB receptor dimers have been identified. It has been shown that some of these receptor pathways communicate with each other via crossconnected regulatory networks. Molecular interactions between retinoid receptors or estrogen receptors (ER) and cerbB2, and between ER and retinoic acid receptor(RAR) have been reported. Here, we demonstrate the effects of steroids/thyroids/retinoids and of activators of protein kinase A (forskolin, Forsk) and C (12Otetradecanoylphorbol13acetate, TPA), on growth and expression of cerbB and RARs in MCF7 breast cancer cells, which contain high levels of RAR and , and which express significant amounts of cerbB2 and 3. All transretinoic acid (tRA), the antiestrogen ICI 182 780 (ICI), Forsk and TPA reduced, whereas triiodothyronine and 17estradiol (E₂) stimulated cell growth. Flow cytometry revealed that tRA and E₂ reduced cerbB2 and 3, whereas tamoxifen, Forsk and TPA upregulatedcerbB2. cerbB3 was coregulated with cerbB2. Northern analysis demonstrated that RAR was downregulated by dexamethasone, ICI, and TPA, whereas vitamin D₃ and E₂ upregulated RAR. RAR expression was less responsive to such treatment, being reduced only by ICI and Forsk. These data indicate that nuclear receptor and protein kinase signaling communicate with each other and control the expression of RARs and cerbB receptors. Efficient growth control requires the coordinated interplay of both receptor systems.     

Epirubicin and doxorubicin comparative metabolism and pharmacokinetics

Summary The pharmacokinetics and metabolism of doxorubicin (DX) and epirubicin (epiDX) were investigated in eight cancer patients who received 60 mg/m² of both drugs independently by intravenous (i.v.) bolus at 3-week intervals according to a balanced cross-over design. Unchanged DX and epiDX plasma levels followed a triexponential decay. Half-lives (t/2) of the three decay phases were longer for DX (t/2: 4.8 vs. 3 min; t/2 2.57 h vs. 1.09 h; t/2 48.4 vs. 31.2 h). According to a model-independent analysis, the different plasma disposition kinetics of the two compounds appears to be related to a higher plasma clearance (PlCl) and to a lower mean residence time (MRT) of epiDX (PlCl: 75.0 l/h, range: 35.6–133.4 l/h; MRT: 31.6 h, range: 7.0–41.5 h;) compared to DX (PlCl: 56.8 l/h, range: 24.4–119.5; MRT: 45.6 h, range: 26.0–83.1 h). No statistically significant differences could be detected for the volume of distribution at steady state (Vss) (epiDX, 31.8 l/kg; DX, 33.3 l/kg). Metabolites common to both compounds were detected in plasma: the 13-dihydro derivatives doxorubicinol (DXol) and epirubicinol (epiDXol), together with monor amounts of four aglycones (7-deoxy adriamycinone, adriamycinone, 7-deoxy 13-dihydro adriamycinone, and 13-dihydro adriamycinone). Following epiDX administration, two additional major metabolites were detected: the glucuronic acid conjugates of epiDX (4-O--d-glucuronyl-4-epiDX) and epiDXol (4-O--d-glucuronyl 13-dihydro-4-epiDX). This additional detoxication route appears to account for the more efficient and faster elimination of epiDX than of DX. In the urine collected in the 6 days after treatment, 12.2% of the DX and 11.9% of the epiDX dose was excreted as unchanged drug and fluorescent metabolites. A comparable renal clearance was calculated for DX (4.7 l/h, range 1.4–7.0 l/h) and epiDX (4.4 l/h, range 1.7–7.0 l/h). One patient with hepatic metastates and abnormal bilirubin serum level had percutaneous biliary drainage because of extrahepatic obstruction. The elimination of both drugs was significantly impaired in this patient; nevertheless, elimination of epiDX was still more efficient and faster than that of DX (PlCl: 35.6 vs. 24.4 l/h; MRT: 39.0 vs. 83.1 h; t/2: 47 vs. 74 h). This patient's biliary excretion accounted for 35.4% of the epiDX dose and 18.2% of the DX dose.Supported in part by contract CNR, No. 85.02282.44 (Progetto Finalizzato Oncologia)     

The α6β1 and α6β4 integrins in human prostate cancer progression

Summary Prostatic secretions are formed by glands composed of basal and luminal cells and surrounded by a basal lamina. The normal basal cells express several integrins (extracellular matrix receptors) including alpha 2, 3, 4, 5, 6, v, beta 1 and beta 4. These integrin units are polarized at the base of the cells adjacent to the basal lamina. The integrin alpha 6 beta 4 is associated with hemidesmosomal-like structures.The natural history of prostate cancer involves the presence of prostatic intraepithelial neoplasia (PIN) lesions (considered precursor lesions), carcinomain situ and invasive carcinoma. Hemidesmosomal proteins and the 31 and 61 integrins (laminin receptors) are retained in the early PIN lesions. Expression of the integrins 2, 4, 5, v and 4 is lost in carcinoma. The 31 and 61 integrins remain associated with invasive carcinoma, the latter being predominant. Integrin expression in carcinoma is diffuse in the plasma membrane and not restricted to the basal aspects of the cell. The 61 integrin is fully functional as judged by an ability to adhere to laminin and contains the wild type 6A cytoplasmic signaling domain. The 61 integrin is a leading candidate for conferring the invasive phenotype in prostatic carcinoma.Tumor cells with high expression of 6 integrin are more invasive when tested in a SCID mouse model system. Following intraperitoneal injection, the human tumor cells invade the mouse diaphragm and move through the muscle on the surface of the laminin coated muscle cells. Our current working hypothesis is that the production of 61 and laminin in human tumor cells contributes to the invasive phenotype. Invasion could occur on the surfaces of laminin coated structures such as the nerves, blood vessels or muscle and account for the known patterns of human prostate tumor progression. Blockage of the expression or function of 61 or laminin or preventing the loss of 4 would be essential steps in confining the carcinoma to the prostate gland where conventional treatment has already proven effective.     

β-Carotene and/or vitamin E as modulators of alkylating agents in SCC-25 human squamous carcinoma cells

Summary Dietary levels of -carotene and vitamin E have been associated with cancer prevention and to a lesser extent, with therapeutic enhancement of cancer treatment. We report on the cytotoxicity of -carotene, vitamin E, and the combination of -carotene and vitamin E in human SCC-25 squamous carcinoma cells under various environmental conditions found in solid tumor masses. -Carotene was selectively cytotoxic toward normally oxygenated cells and was generally more cytotoxic at normal pH than at acidic pH (6.45). Vitamin E was selectively cytotoxic toward normally oxygenated cells following 6 h exposure at normal pH and was generally equally cytotoxic toward normally oxygenated and hypoxic cells under the other conditions tested. -Carotene was an effective modulator of cisplatin (CDDP) cytotoxicity toward SCC-25 cells, whereas vitamin E was not. Both -carotene and vitamin E were effective modulators of melphalan cytotoxicity toward SCC-25 cells. Treatment of SCC-25 cells with -carotene (70 m, 2h) resultec in a reduction in superoxide dismutase activity, in glutathione-S-transferase activity, and in nonprotein sulfhydryl levels in the cells. Exposure to vitamin E or to a combination of -carotene and vitamin E increased the glutathione-S-transferase activity in SCC-25 cells by 40%–45% over the control value. Treatment with -carotene, vitamin E, or canthaxanthin reduced the incorporation of [³H]-thymidine into SCC-25 cells but not that into normal human karotinocytes. The most marked reduction in [³H]-thymidine incorporation into SCC-25 cells occurred following treatment with the combination of -carotene and melphalan. We hope to continue to explore the mechanisms of this effect and to study these combinations in vivo.This work was supported by NIH grant PO1-38 493, by a grant from Bristol-Mycrs-Squibb (Wallingford, Conn.), and by a grant from Cancer Prevention Technologies, Inc. (Basking Ridge, N. J.)     

Neuroblastoma and parental occupation

Objectives: We evaluated parental occupation and the risk of neuroblastoma using data from a large case–control study conducted by the Children's Cancer Group and the Pediatric Oncology Group.Methods: We compared the distribution of 73 paternal and 57 maternal occupational groups among 504 newly diagnosed cases of neuroblastoma and individually matched controls obtained by telephone random digit dialing in the United States and Canada.Results: An increased risk of neuroblastoma was found for fathers employed as broadcast, telephone and dispatch operators (odds ratio [OR]=6.1; 95% confidence interval [CI]=0.7–50.9), electrical power installers and power plant operators (OR=2.7; CI=0.9–8.1), landscapers and groundskeepers (OR=2.3; CI=1.0–5.2), and painters (OR=2.1; CI=0.9–4.8). Elevated odds ratios were found for mothers employed as farmers and farm workers (OR=2.2; CI=0.6–8.8), florists and garden store workers (OR=2.4; CI=0.6–9.9), hairdressers and barbers (OR=2.8; CI=1.2–6.3), electric power installers and power plant operators, and sailors, fishers, and railroad workers. No increase in risk was found for other paternal occupations previously associated, including electricians, electrical equipment assemblers and repairers (OR=1.1; CI=0.6–2.0), or welders (OR=0.5; CI=0.1–1.6).Conclusion: The study reinforced some prior evidence of increased risks in electrical, farming and gardening, and painting occupations, but failed to confirm other previously reported associations. Further analyses of exposure to electromagnetic fields, metals, solvents, and pesticides are currently under way.     

Is salvage chemotherapy for metastatic breast cancer always effective and well tolerated? A phase II randomized trial of vinorelbine versus 5-fluorouracil plus leucovorin versus combination of mitoxantrone, 5-fluorouracil plus leucovorin

Metastatic breast cancer remains an incurable disease and the median overall survival has not significantly improved over the past two decades. Aims of the present randomized phase II trial were to analyse activity and toxicity of chemotherapies with single agent or with combination regimens in previously treated patients with advanced breast cancer. Ninety-nine eligible patients were randomized to receive the following chemotherapies: Arm A – 30mg/m² i.v. weekly; Arm B – leucovorin 100mg/m² i.v. followed by 5-fluorouracil 370mg/m² i.v. days 15, q 28days; Arm C – mitoxantrone 12mg/m² i.v. only day 1+leucovorin 100mg/m² i.v. followed by 5-fluorouracil 370mg/m² i.v. days 13, q 28days. Patients characteristics are comparable in the three groups. The median number of chemotherapy courses administered was 7, 6 and 5 in arm A, B and C, respectively. Objective responses were 24%, 30% and 21% and the median duration of responses were 2, 2.5 and 5.5 months in the arm A, B and C, respectively. Median overall survivals were 9.5, 9 and 9 months in the three arms. No difference was noted comparing the survivals of responding or non responding patients. General toxicity was not mild, with 27.5% of patients experiencing WHO grade 3–4 toxicities.Our results are similar in the three groups of patients and comparable to those reported by other authors. Chemotherapy applied to patients with second or subsequent recurrence allow objective responses in a small percentage of patients. Moreover responders have a negligible prolongation of survival.     

Phenotypic analysis of 1-B-d-arabinofuranosylcytosine deamination in patients treated with high doses and correlation with response

Summary Two phenotypes for 1-B-d-arabinofuranosylcytosine (ara-C) deamination corresponding to a ratio of distribution for slow (ratio, 14) vs fast (ratio, >14) deaminators of 70%30%, have been determined on the basis of studies on plasma ratios of 1-B-d-arabinofuranosyluracil/ara-C (ara-U/ara-C) in 56 subjects treated with high-dose ara-C (3 g/m² infused i.v. over 3 h). A positive correlation of age with the concentration of ara-U was observed. In a subgroup of 36 patients with leukemia, the ara-U/ara-C pattern was similar to that observed for all 56 subjects. In these leukemic patients, who were treated with combinations of ara-C plus other conventional agents, a tendency toward a positive response (complete response +partial response) was found for those showing low ara-U/ara-C ratios (slow deaminators). The phenotypic effect of deamination in acute leukemia needs to be evaluated prospectively.This work was supported by the Don Monti Memorial Research Foundation     

Synergistic action of apoptosis induced by eicosapentaenoic acid and TNP‐470 on human breast cancer cells

The effects of eicosapentaenoic acid (EPA) and an angiogenesis inhibitor (TNP470) on the suppression of breast cancer cell growth were examined in five human breast cancer cell lines (MDAMB231, T47D, MCF7, KPL1, and MKLF). In all five cell lines, EPA and TNP470 alone both showed tumor growth inhibition in a time and dosedependent manner, and in combination, a synergistic effect was seen at high concentrations. EPA plus TNP470 treatment evoked apoptosis as confirmed by the appearance of sub G1 populations, by DNA fragmentation, and by cell morphology. With the combination, the expression of Bax and Bc1x_S, the apoptosisenhancing proteins, was more upregulated and that of Bcl2 and Bclx_L, the apoptosissuppressing proteins, was more downregulated compared to the use of EPA or TNP470 alone, suggesting that their synergistic effect was due to an acceleration of apoptosis.     

Coexpression of c-kit and stem cell factor in breast cancer results in enhanced sensitivity to members of the EGF family of growth factors

Insulinlike growth factor (IGF)I protects many cell types from apoptosis. As a result, it is possible that IGFIresponsive cancer cells may be resistant to apoptosisinducing chemotherapies. Therefore, we examined the effects of IGFI on paclitaxel and doxorubicininduced apoptosis in the IGFIresponsive breast cancer cell line MCF7. Both drugs caused DNA laddering in a dosedependent fashion, and IGFI reduced the formation of ladders. We next examined the effects of IGFI and estradiol on cell survival following drug treatment in monolayer culture. IGFI, but not estradiol, increased survival of MCF7 cells in the presence of either drug. Cell cycle progression and counting of trypanblue stained cells showed that IGFI was inducing proliferation in paclitaxeltreated but not doxorubicintreated cells. However, IGFI decreased the fraction of apoptotic cells in doxorubicin but not paclitaxeltreated cells. Recent work has shown that mitogenactivated protein kinase (MAPK) and phosphotidylinositol3 (PI3) kinase are activated by IGFI in these cells. PI3 kinase activation has been linked to antiapoptotic functions while MAPK activation is associated with proliferation. We found that IGFI rescue of doxorubicininduced apoptosis required PI3 kinase but not MAPK function, suggesting that IGFI inhibited apoptosis. In contrast, IGFI rescue of paclitaxelinduced apoptosis required both PI3 kinase and MAPK, suggesting that IGFImediated protection was due to enhancement of proliferation. Therefore, IGFI attenuated the response of breast cancer cells to doxorubicin and paclitaxel by at least two mechanisms: induction of proliferation and inhibition of apoptosis. Thus, inhibition of IGFI action could be a useful adjuvant to cytotoxic chemotherapy in breast cancer.     

Effects of supplemental α-tocopherol and β-carotene on colorectal cancer: results from a controlled trial (Finland)

Background:Some epidemiological investigations suggest that higher intake or biochemical status of vitamin E and -carotene might be associated with reduced risk of colorectal cancer. Methods:We tested the effects of -tocopherol and -carotene supplementation on the incidence of colorectal cancer in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, a double-blind, placebo-controlled trial among 29,133 50–69-year-old male cigarette smokers. Participants were randomly assigned to receive -tocopherol (50mg), -carotene (20mg), both agents, or a placebo daily for 5–8 years. Incident colorectal cancers (n=135) were identified through the nationwide cancer registry, and 99% were histologically confirmed. Intervention effects were evaluated using survival analysis and proportional hazards models. Results:Colorectal cancer incidence was somewhat lower in the -tocopherol arm compared to the no -tocopherol arm, but this finding was not statistically significant (relative risk (RR)=0.78, 95% confidence interval (CI) 0.55–1.09; log-rank test p=0.15). -Carotene had no effect on colorectal cancer incidence (RR=1.05, 95% CI 0.75–1.47; log-rank test p=0.78). There was no interaction between the two substances. Conclusion:Our study found no evidence of a beneficial or harmful effect for -carotene in colorectal cancer in older male smokers, but does provide suggestive evidence that vitamin E supplementation may have had a modest preventive effect. The latter finding is in accord with previous research linking higher vitamin E status to reduced colorectal cancer risk.     

Inhibition of cell proliferation and glutathione S-transferase by ascorbyl esters and interferon in mouse glioma

Summary Mouse glioma-26 (G-26) cell line established in this laboratory was used in the study. Thein vitro effect of ascorbyl esters, viz., ascorbyl-palmitate (As-P), -stearate (As-S) and mouse interferon-/ (MulFN-/) on the glioma cell viability, proliferation and glutathione S-transferase (GST) activity was investigated. Cell viability and proliferation were examined by colorimetric MTT assay and [³H]-thymidine incorporation, respectively. Incubation (24 h) of G-26 cells with As-S, As-P or MulFN-/, resulted in a dose dependent decrease in cell viability (IC₅₀=125M As-S; 175M As-P and 3.6×10⁴ U/ml MulFN-/) and proliferation (IC₅₀=157M As-S; 185M As-P and 3.6×10⁴ U/ml MulFN-/). A combined exposure to 175 M As-S and 800 U/ml of MulFN-/ resulted in a greater than an additive effect on cell viability and proliferation. The inhibition of cell proliferation/viability by interferon was species specific and was observed only with homologous MulFN-/, but not with human interferon- lymphoblastoid or human interferon-. Ascorbyl esters inhibited cytosolic GST activity (1–50=15.0 M As-S and 28.5 M As-P) towards 1-chloro-2,4-dinitrobenzene in a dose dependent manner. The apparent Ki values for affinity purified GST, deduced from Dixon plots were 0.95 M and 2.0 M for As-S and As-P, respectively. Significant inhibition of GST was also observed in the cytosol isolated from G-26 cells exposed to 300 M As-S or 800 U/ml MulFN-/.