Changes in fos/jun binding-activity on a negative regulatory element of C-myc during differentiation of mouse erythroleukemic cells

The binding activity of the AP-1 FOS/JUN complex to a negative regulatory element on the c-myc promoter was investigated and correlated with events characteristic of terminal differentiation of HMBA-induced mouse erythroleukemic cells. It is suggested that the altered AP-1 activity that was found upon induction of the erythroid differentiation may contribute to the late decline in c-myc mRNA.

CD40 activation-induced, Fas-dependent apoptosis and NF-kappaB/AP-1 signaling in human intrahepatic biliary epithelial cells

Fas-mediated mechanisms of apoptosis are thought to be involved in the bile duct loss that characterizes diseases such as primary biliary cirrhosis (PBC). We have previously shown that activation of CD40 on hepatocytes can amplify Fas-mediated apoptosis; in the present study, we investigated interactions between CD40 and Fas in biliary epithelial cells (BEC). We report that the bile ducts in PBC liver tissue frequently express increased levels of Fas, Fas ligand (FasL), and CD40 associated with apoptotic BEC. The portal mononuclear infiltrate contains CD40L+ve T cells and macrophages, thereby demonstrating a potential mechanism for CD40 engagement in vivo. Primary cultures of human BEC also expressed Fas, FasL, and CD40 but not CD40L protein or mRNA. Activation of CD40 on BEC using recombinant CD40L increased transcriptional expression of FasL and induced apoptosis, which was inhibited by neutralizing antibodies to either Fas or FasL. Thus, CD40-induced apoptosis of BEC is mediated through Fas/FasL. We then investigated the intracellular signals and transcription factors activated in BEC and found that NF-kappaB and AP-1 were both activated after CD40 ligation. Increased functional NF-kappaB was seen early after CD40 ligation, but returned to baseline levels after 4 h. In contrast, the rapid up-regulation of AP-1 was sustained over 24 h. This study provides further functional evidence of the ability of CD40 to induce Fas/FasL-dependent apoptosis of liver epithelial cells supporting the importance of cross-talk between tumor necrosis factor (TNF) receptor family members as an amplification step in apoptosis induction. Sustained activation of AP-1 in the absence of NF-kappaB signaling may be a critical factor in determining the outcome of CD40 engagement.

Phase I trial of weekly scheduling and pharmacokinetics of titanocene dichloride in patients with advanced cancer

PURPOSE

To determine the maximum-tolerated dose (MTD) and the dose-limiting toxicities (DLTs) of a weekly schedule of titanocene dichloride (TD) and to define the pharmacokinetics of titanium in plasma and urine.

PATIENTS AND METHODS

Twenty patients with a median age of 58 years received 83 courses of TD. TD was given as 1-hour infusion at escalating doses from 70 to 185 mg/m2/wk. Pharmacokinetic analysis was performed in eight patients for total plasma titanium (TPTi) and in three patients for ultrafiltrable titanium (UFTi).

RESULTS

At the fifth dose level (185 mg/m2/wk), a variety of DLTs were seen in five patients: fatigue in three, bilirubinemia in one, and hypokalemia in two. A further six patients were treated at 140 mg/m2; only one had dose-limiting creatinine elevation and this dose was therefore defined as the MTD. No myelosuppression or alopecia were observed. One patient with adenocarcinoma of unknown primary had a minor response. Pharmacokinetic analysis showed that TPTi maximum concentration (Cmax) values were linear with dose and elimination of TPTi was triphasic with a long terminal half-life (t1/2; median, 165 hours; range, 89 to 592). Between 7% and 24.3% of the total of administered titanium was eliminated in urine over the first 24 hours. In contrast, UFTi elimination was described by a one-compartment model with a t1/2 of 0.41 hours; peak levels of UFTi were 5.2% +/- 2.5% those of TPTi.

CONCLUSION

The MTD of TD given on a weekly schedule is 140 mg/m2, with cumulative, but reversible creatinine and bilirubin elevation being the DLTs.

Expression of ras p21, p53 and c-erbB-2 in advanced breast cancer and response to first line hormonal therapy

Several oncogenes and tumour-suppressor genes have been identified that may have an important role in the development of human breast carcinoma. Furthermore, some of these gene alterations may be linked to the development of invasion and subsequent metastasis. Alterations in the expression of ras p21, p53 and c-erbB-2 have all been linked to tumours with rapid cellular proliferation, but the evidence that they are of prognostic importance in patients with breast cancer is conflicting. This study explores the relationship between expression of these oncoproteins and clinical outcome in 92 patients with either locally advanced or metastatic breast cancer treated with primary endocrine therapy. Specimens of the primary carcinoma were available for analysis of hormone receptor, Ki67 labelling index, epidermal growth factor receptor (EGFR), c-erbB-2, p53 and ras p21. Clinical response was measured according to UICC criteria after 6 months of treatment and all patients were followed for time to progression and overall survival. As shown previously, oestrogen receptor (ER) negativity, high Ki67 labelling index and EGFR overexpression were associated with a shorter time to progression and overall survival. However, no statistically significant relationship existed between expression of ras p21, p53 or c-erbB-2 and response to treatment, time to progression or overall survival. We conclude that staining for these three oncoproteins has no role in therapeutic decision-making in patients with advanced breast cancer. The negative finding implies that while abnormal expression of these genes may have an important role in the development of breast cancer, the variations in growth characteristics of advanced breast cancer may be influenced by other factors.

Ras gene-mutations are a rare event in human uveal and cutaneous melanomas

Melanomas are malignant tumours with high metastatic potential. The genetic alterations which lead to the transformation and progression of melanocytes to malignant melanoma remain obscure. Mutations in the ras gene family have been described, however their role in melanoma pathogenesis is still controversial. In this study we examined the incidence of H-, K- and N-ras mutations in 47 DNA samples isolated from paraffin-embedded 25 cutaneous and 22 uveal malignant melanoma tissues and a MeWo melanoma cell line using the Restriction Fragment Length Polymorphism (RFLP) analysis of PCR products. Only one mutation in codon 61 of the N-ras gene was found suggesting that the importance of ms mutations in melanoma tumourigenesis may be limited.

The effect of cisplatin and carboplatin on c-myc promoter in erythroleukemic cells

The recombinant plasmids p324, p330 and p323 carrying 5' flanking c-myc sequences linked to the reporter gene chloramphenicol acetyl-transferase (cat) were introduced into the mouse erythroleukemia cell line F412B2TK- and stable transfectants resistant to geneticin were obtained. The effects of two platinum coordination compounds, cisplatin and carboplatin, were studied using a wide range of drug concentrations. It was found that cisplatin stimulates cat gene expression with maximum effect at 5 x 10(-5) M concentration, while carboplatin at concentrations from 1 x 10(-6) to 1 x 10(-4) M did not have any effect. These results demonstrate that cisplatin stimulates transcription from the c-myc promoter in erythroleukemia cells and may support the use of carboplatin as compared to cisplatin in the treatment of cancer patients.

The effect of doxorubicin, daunorubicin and 4'-epidoxorubicin on the exogenous c-myc promoter in mouse erythroleukemia cells

The recombinant plasmids p324, p330 and p323 carrying the aminoglycoside phosphotransferase (aph) gene and 5' flanking c-myc sequences linked to the reporter gene chloramphenicol acetyl-transferase (cat) were introduced into the mouse erythroleukemia cell line F412B2TK- and stable transfectants resistant to geneticin were obtained. The effects of three anthracycline compounds, doxorubicin, daunorubicin and 4'-epidoxorubicin, were studied using a large range of drug concentrations. It was found that 4'-epidoxorubicin and daunorubicin stimulate cat-gene expression with maximum effect at a concentration of 1 micrograms/ml, while doxorubicin enhances transcription from c-myc promoter at 5 micrograms/ml.

Defective mitogen-induced cellular cytotoxicity in myelodysplastic syndromes. Recovery after alpha-interferon administration

Peripheral blood mitogen - induced cellular cytotoxicity (MICC) and natural killer- cell cytotoxicity (NKCC) were assessed in 25 patients with myelodysplastic syndromes (MDS). Both MICC and NKCC were examined under the same experimental conditions using the 18 hr chromium release assay, except that cultures for MICC were stimulated in vitro by the addition of phytohemagglutinin (PHA). Patients' MICC was found significantly reduced, in relation to controls (p less than 0.001), but significantly higher than patients' NKCC (p less than 0.001). Furthermore, patients CD3+ cells and CD4+ cells, as well as the CD4+/CD8+ ratio, were significantly decreased (p less than 0.01, p less than 0.001 and p less than 0.001, respectively), while CD8+ cells and CD16+ cells were within normal limits. No relationship was noted between patients' MICC and total lymphocyte count or any lymphocyte subpopulation. In eleven patients who were subsequently subjected to a-interferon (a-IFN) administration, MICC values were found within normal range one month after the cessation of alpha-IFN, while NKCC values were significantly increased (p less than 0.01), but they still remained below the lower limit of the control (p less than 0.001). Percentages of CD3+, CD4+ and CD8+ cells, as well as the CD4+/CD8+ ratio, did not change after alpha-IFN, but the absolute numbers of CD3+ cells and CD8+ cells were significantly reduced. A statistically significant rise was noted in CD16+ cells. Post- IFN rises in MICC did not correlate with lymphocyte subpopulations. The findings indicate that MDS patients display very low MICC, which can be restored by alpha-IFN administration. The cause of this disturbance and the mechanism of its restoration by alpha-IFN remain unclear.

Antiemetic efficacy of high-dose dexamethasone: randomized, double-blind, crossover study with high-dose metoclopramide in patients receiving cancer chemotherapy

A double-blind, randomized, crossover study was conducted to compare the efficacy and safety of high-dose dexamethasone and high-dose metoclopramide in the treatment of chemotherapy-induced nausea and vomiting. All entered patients had no prior chemotherapy and all received inpatient emetogenic chemotherapy mainly without cisplatin. Of the 40 evaluable patients, 23 (58%) had no vomiting with dexamethasone compared with only 11 (28%) receiving metoclopramide (P less than 0.025). Dexamethasone was found to have less adverse effect than metoclopramide on patient's appetite and activity (P less than 0.025 and P less than 0.01, respectively). Twenty-one patients (53%) developed mild to severe somnolence with metoclopramide compared to only seven (18%) who experienced this adverse effect with dexamethasone (P less than 0.01). Six patients (15%) developed extrapyramidal manifestations with metoclopramide, but none with dexamethasone. Furthermore, during dexamethasone therapy, patients developed less diaphoresis, insomnia, headache and dizziness. Upon questioning patients about their preference to future use of the antiemetic drug therapy, 28 patients (70%) preferred dexamethasone, two (5%) preferred metoclopramide and 10 (25%) found no difference. We conclude that high-dose dexamethasone has a greater antiemetic activity and is more safe than high-dose metoclopramide in patients receiving emetogenic chemotherapy mainly without cisplatin.